Short Division with Remainders

Short Division with Remainders

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what are remainders in maths division

  • A remainder is the amount left over after a number has been shared equally.
  • 7 ÷ 3 is not an exact division so it will have a remainder.
  • We can share 7 sweets between 3 people so that they each get 2 sweets and one is left over.
  • We say that 7 ÷ 3 = 2 remainder 1.
  • We can write remainders ‘r’ for short.

    We can write 7 ÷ 3 = 2 r1.

  • The remainder of 1 is the difference between 7 and 3 × 2.

The remainder is amount left over after a division.

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Short Division with Remainders example

  • We have the short division of 625 ÷ 2.
  • We divide each digit by 2 separately working from left to right.
  • 6 ÷ 2 = 3.
  • 2 ÷ 2 = 1.
  • 2 does not divide exactly into 5.
  • 2 × 2 = 4 which is 1 less than 5.
  • 2 goes into 5 twice, with 1 left over.
  • 5 ÷ 2 = 2 remainder 1.
  • We can write 5 ÷ 2 = 2 r1.

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Short Division with Remainders Interactive Questions

Short Division with Remainders Interactive Question Generator

Short Division with Remainders Worksheets and Answers

The Short Division Method with Remainders

What are remainders?

In maths, a remainder is the number that is left over after a division. A remainder is the difference between the number being divided and the largest multiple less than this number.

For example, 7 ÷ 3 = 2 remainder 1, because 3 × 2 = 6 and the difference between the number 7 and 6 is 1.

We write ‘remainder’ as ‘r’ for short. We write this r in before the remainder value.

So we can write 7 ÷ 3 = 2 remainder 1 as:

7 ÷ 3 = 2 r 1

what are remainders in maths division.

We can see that if we share 7 sweets equally amongst 3 people, they each get 2 sweets but there is 1 left over. We call this extra 1 a remainder. We have a remainder of 1.

Short Division with Remainders

We will look at how to perform larger divisions with remainders by using the short division method.

In this example we have 625 ÷ 2.

We write the number being divided with a line to the left and above of it. The shape of this line often means that this method is called the ‘bus stop method’ for division.

We will divide each digit in the number 625 by 2 separately.

625 divided by 2 set out with the short division method

We work from left to right, starting with the 6.

625 divided by 2 set out as a short division

6 ÷ 2 = 3

We write the 3 above the 6 in the short division.

625 divided by 2 set out as a short division

2 ÷ 2 = 1

We write the 1 above the 2.

We now look at the final digit.

2 does not divide exactly into 5.

2 × 2 = 4 and we need 1 more to make 5.

5 ÷ 2 = 2 r1

625 divided by 2 = 312 remainder 1, set out as a short division

2 divides into 5 twice, with 1 left over. We write the 2 above the 5.

There are no more digits to divide by, so we write the leftover 1 as a remainder at the end of our answer.

We write this remainder as ‘r1’.

example of short division with a remainder 625 ÷ 2

Therefore,

625 ÷ 2 = 312 r 1.

Here is another example of short division involving remainders:

498 divided by 4 set out with the short division method

We set out the short division calculation as shown above. We want to divide each digit in 498 by 4.

We work from left to right, starting with the 4.

498 divided by 4 set out as a short division

4 ÷ 4 = 1

We write the 1 above the 4 in our division.

498 divided by 4 set out as a short division

9 ÷ 4 = 2

4 divides into 9 twice with 1 left over.

We write the 2 above the 9 and write the leftover 1 in front of the next digit along.

We now have 18 ÷ 4.

498 divided by 4 = 124 remainder 2,set out as a short division

18 ÷ 4 = 4

4 divides into 18 4 times, with 2 left over. We write the 4 above the 18.

There are no more digits to divide by, so we can write the leftover 2 as a remainder at the end of our answer.

We write the remainder as ‘r2’, which stands for ‘remainder 2’.

Example of short division with remainders 498 ÷ 4

Therefore,

498 ÷ 4 = 124 r2.

Checking the Answer to a Short Division Problem

To check the answer to a division problem, multiply the answer by the number you have divided by. If the answer is correct, the result will be the original number that was divided.

If there is a remainder, multiply the whole number part of the answer by the number you divided by and then add the remainder on separately at the end.

In the example above, we divided 498 by 4 and got an answer of 124 r2.

To check the result we multiply the whole part of the answer by 4 and then add on the remainder.

4 × 124 = 496 and adding the remainder of 2, we get 498.

This is the original number that we divided in the question and so, this division is correct.

In this next example of short division with remainders we have 814 ÷ 3.

We divide each digit in 814 separately by 3.

8 ÷ 3 = 2 with 2 left over. This is because 3 goes into 8 twice to make 6. We need to add 2 more to 6 to get to 8.

We carry this ‘2’ over to the ‘1’ in the next column to make ’21’.

21 ÷ 3 = 7. This divides exactly and so, there is no remainder to carry.

Finally 4 ÷ 3 = 1 r1. This is because 3 goes into 4 once with 1 left over.

Short Division with Remainders example of 814 divided by 3

We have divided all of the digits and so, this remainder of 1 is written at the end of the answer.

814 ÷ 3 = 271 r1.

To check the answer to this division problem, we multiply 271 by 3 and add the remainder on at the end.

271 × 3 = 813 and adding the remainder of 1 we get 814.

This is the original number that we started with and so, the division is correct.

In this next example of short division with remainders we have 819 ÷ 5.

8 ÷ 5 = 1 r3 because 5 goes into 8 once with 3 more needed to get to 8.

We carry the remainder of ‘3’ over to the next digit along ‘1’ to make ’31’.

31 ÷ 5 = 6 remainder 1 because 5 × 6 = 30 and 1 more is required to make 31.

We carry this remainder of ‘1’ over to the ‘9’ to make ’19’.

19 ÷ 5 = 3 remainder 4 because 5 × 3 = 15 and 4 more is needed to make 19.

Example question of short division with Remainders 819 divided by 5

We have divided all of the digits in the number and so, we write the remainder at the end of our answer.

819 ÷ 5 = 163 remainder 4, which we can write as 163 r4.

To check the answer to this short division problem, we can multiply 163 by 5 and then add on the remainder of 4.

163 × 5 = 815 and adding the remainder of 4 makes 819.

This is the original number that we were dividing and so, the answer to the division is correct.

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Now try our lesson on Short Division: Remainders as Fractions where we learn how to write the remainders as fractions.

Introduction to Writing Algebraic Terms

Introduction to Writing Algebraic Terms

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introduction to algebraic terms example with apples

  • We use letters in algebra when we don’t know the value of something.
  • These letters can be called variables.
  • We don’t know how much each apple costs, so we say each apple costs ‘a’.
  • The total cost of three of these apples is a + a + a, which is 3 lots of a.
  • We don’t write the multiplication sign in algebra because we use the letter ‘x’ a lot which looks similar.
  • We write a + a + a as 3a, which means that there are 3 a’s.
  • We always write the number in front of the letter.

We do not write multiplication signs with algebra.

We write how many of each letter there are with a number in front of the letter.

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example of basic algebra collecting like terms

  • Here is b + b + b.
  • We have 3 b’s in total.
  • We can write b + b + b as 3b.
  • We don’t write 3 × b because we don’t write multiplication signs in algebra.
  • We always write the number in front of the letter, so we write 3b and not b3.

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Collecting Algebraic Terms Worksheets and Answers

Introduction to Writing Algebra

What are Algebraic Terms?

Algebraic terms are the different letters or numbers in an expression that are separated by plus or minus signs. A single term can even contain multiple different letters and numbers multiplied together. As long as there is not a plus or minus sign, then it is an algebraic term.

The letters in a term are called variables and the numbers in front of them are called coefficients.

For example, in the expression: c + c + c + c, we have 4 algebraic terms. Each letter ‘c’ is separated by a plus sign, so each letter ‘c’ is a separate term.

expression with 4 algebraic terms

In most cases, the algebraic terms will be different letters, such as in the next example below.

It is important to note that even numbers on their own can be algebraic terms. It is not necessary to have an algebraic variable present for it to be classed as a term. In this example of d – 3 + e, we have 3 terms.

example of algebraic expression with 3 terms

The first term is ‘d’, the second term is ‘3’ and the third term is ‘e’.

We can see that in this example, the terms are separated by both plus and minus signs.

Remember, if there is not a plus or minus sign separating the letters or numbers, then it is one single term.

For example in the expression: 2a – 4cd there are 2 terms. The first term is ‘2a’ and the second term is ‘4cd’.

example of algebraic terms with coefficients

How to Write Algebraic Terms

When writing algebraic terms use the following rules:

  • Do not write multiplication signs.
  • Write the number in front of the letters in each term.
  • If there is only one of a certain algebraic term, do not write the number 1 in front of it. Simply write the letters only.

For example, here is the expression 𝑥 + 𝑥. There are two 𝑥 terms.

𝑥 + 𝑥 is the same as 2 × 𝑥.

The multiplication sign of ‘×’ and the variable ‘𝑥’ look very similar. 𝑥 is a letter that is commonly used in algebra. For this reason, we do not use the multiplication sign in algebra. Removing the multiplication sign also keeps the algebraic expressions shorter and simpler to work with.

Instead of 2 × 𝑥 we write 2𝑥.

We don't write the times sign in algebra. example of simplifying terms with x.

2𝑥 means that we have 2 × 𝑥, or 2 x’s.

An important rule used when writing algebraic terms is to avoid using the number 1 in front of an algebraic variable if there is only 1 of them.

For example, here is the variable 𝑥.

Although we only have 1 𝑥, we simply write 𝑥.

We do not write 1𝑥.

we do not write 1 in algebra

The reason we do not write 1 in front of algebraic terms is because we don’t need to. It is quicker and easier, especially in longer algebraic expressions to avoid using the number 1. It is easier to write 𝑥 than it is to write 1𝑥.

This is just a simple example and when it comes to more complex expressions and equations, it can be helpful to remove unnecessary information.

In this example, we have y + y + y + y + y.

We have 5 ‘y’ terms, which is 5 lots of y, or 5 × y.

We do not write the multiplication symbol and so, y + y + y + y + y = 5y.

simplifying an algebraic expression in terms of y

5y simply means that we have 5 y terms.

We can see that it is quicker to write 5y than it is to write y + y + y + y + y.

We can do this because all of the terms are y terms. There is no other letter in the expression.

Counting up the same letter terms is known as collecting like terms and is explored in a different lesson Collecting Like Terms.

Here is another example of collecting like terms.

In this expression, we have b + b + b.

collecting like terms in an expression

We have 3 b terms, so we write this as 3b.

Remember that we do not write the multiplication sign and we always write the number in front of the letters.

We write 3b, not b3.

The number that comes in front of the algebraic variables (letters) is called the coefficient.

coefficients and variables diagram

In the example of 5ab, 5ab is one term. ‘5’ is the coefficient and both ‘a’ and ‘b’ are the variables.

Writing the Letter 𝑥 in Algebra

In this example we have: 𝑥 + 𝑥 + 𝑥 + 𝑥.

We have 4 𝑥’s in total or 4 × 𝑥.

Remember, we do not write the multiplication sign so we simply write 𝑥 + 𝑥 + 𝑥 + 𝑥 as 4𝑥.

example of collecting like terms with 𝑥 in algebra.

𝑥 is a letter commonly used in algebra. You may notice that 𝑥 is written differently to the letter x on your keyboard.

In algebra, 𝑥 is written differently to the usual letter x. The letter x looks similar to the multiplication sign, ×. The symbol of 𝑥 is used instead so that it is clearer that we are not doing a multiplication.

To write the algebra 𝑥, write a letter c and then write a letter c backwards just before it.

The algebra 𝑥 is more curved than the standard letter x.

What are Algebraic Variables?

Variables are the letters used in algebra that hold the place of numbers. They are used when the value of something is unknown or can vary, hence the name variable.

For example if the price of an apple is $2, then we can work out the price of three apples by multiplying $2 by 3.

multiplication by repeated addition example problem with three apples each costing $2

$2 × 3 = $6. The total cost would be $6.

However, you might pick up the three apples when shopping and not know what price they are.

You may only find out the price when someone tells you as you go to pay.

Because we do not know the price of each apple, we can use an algebraic variable.

We can use the letter ‘a’ to represent the price of an individual apple.

Any letter can be used, however I chose ‘a’ because it is apples that we are buying. If we were buying bananas, I could still use ‘a’ but I would probably choose ‘b’ to help remind myself what the letter represents.

example of using algebraic variables for the price of apples

We have 3 apples, so the total price is a + a + a.

We have 3 apples, so the total price is 3 × a.

Remember that we do not use multiplication signs in algebra and so we would just write this as 3a.

We say that the total price is 3a.

When teaching or introducing algebra for the first time, people can be uncomfortable with not having a numerical answer. It helps to explain how the answers in these cases will look like and what they mean.

The answer in this case is 3a.

If we later find out the price of an apple is $4, then we can use the algebraic term of ‘3a’ to work out the price.

If a = $4, then 3a means 3 × $4.

If the price of one apple is $4, then the total price of 3 apples would be $12.

The letter ‘a’ is used to hold the value of the apple until we know what it is.

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Now try our lesson on Negative Numbers on a Number Line where we introduce negative numbers.

Difference Between Negatives: Temperature Questions

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How to Find a Fraction of a Number

How to Find a Fraction of a Number

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example of how to find a fraction of a number

  • We will use this bar model to find   2/3   of 18.
  • We want to find two thirds of 18.
  • We can find one third of 18 by dividing by 3.
  • 18 ÷ 3 = 6 and so, one third of 18 is 6.
  • We want two thirds, so we multiply one third by 2.
  • 6 × 2 = 12 and so,   2/3   of 18 = 12.
  • We divided by the number on the bottom of the fraction and multiplied by the number on the top of the fraction.
Multiply by the numerator on top and divide by the denominator on the bottom.

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bar model for finding the fraction of an amount. 3/4 of 20.

  • We want to find   3/4   of 20.
  • To find a fraction of an amount, divide the amount by the denominator on the bottom and then multiply by the numerator on top.
  • Dividing by the denominator: 20 ÷ 4 = 5.
  • Multiplying by the numerator: 5 × 3 = 15.
  • 3/4   of 20 = 15.
  • We can also multiply by the numerator first and then divide by the denominator afterwards to get the same answer.
  • Multiplying by the numerator: 20 × 3 = 60.
  • Dividing by the denominator: 60 ÷ 4 = 15.

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Finding a Fraction of a Number: Interactive Activity

Finding a Fraction of a Number Worksheets and Answers

Finding a Fraction of a Number

How to Find a Fraction of a Number

To find a fraction of a number, follow these steps:

  1. Divide the number by the denominator of the fraction.
  2. Multiply this result by the numerator of the fraction.

For example, to calculate   3/4   of 20, divide 20 by 4 to get 5 and then multiply 5 by 3 to get 15.   3/4   of 20 = 15.

We can see these steps more clearly using the bar model shown below.

The first step is to divide the number by the denominator.

20 ÷ 4 = 5

bar model example to find the fraction of amount 3 quarters of 20

One quarter of 20 is 5. We know this because five fours make twenty.

The second step is to multiply this result by the numerator.

5 × 3 = 15

One quarter is 5, so three quarters are 15.

what are 3 quarters of 20 represented using the bar model method for finding fractions of amounts

We can see three of the quarters are shown shaded on our bar model.

3/4 of 20 example of calculating a fraction of an amount

It does not matter in which order the steps for finding a fraction of a number are done. We can multiply by the numerator first and then divide by the denominator to get the same result.

For example, in   3/4   of 20, we can multiply 20 by the numerator of 3 first.

3 × 20 = 60

Then we can divide this result by the denominator of 4.

60 ÷ 4 = 15

The same result is found whether we multiply or divide first.

When finding the fraction of an amount, it is best to divide by the denominator and then multiply by the numerator afterwards. This is because this order results in multiplying and dividing smaller numbers which is less likely to result in a mistake.

A unit fraction is a fraction with a numerator of 1. A non-unit fraction is any fraction where the numerator is greater than 1.

Here are some further examples of finding a non-unit fraction of a number.

the method for finding a fraction of a number with examples

To find   23 , divide by 3 and then multiply by 2.

To find 34 , divide by 4 and then multiply by 3.

To find 45 , divide by 5 and then multiply by 4.

examples of using a written method to find a fraction of a number

  23 of 18 = 12.

  34 of 20 = 15.

  45 of £30 = £24.

How to Find a Fraction of an Amount

To find a fraction of an amount, simply divide the amount by the denominator on the bottom of the fraction and then multiply this result by the numerator on the top of the fraction.

If there are units in the total amount, simply ignore these for the calculation and then add them back in afterwards.

For example here is the question asking us to find   3/5   of 25 grams.

example of finding a fraction of an amount 3/5 of 25

We first divide 25 by 5 to get 5 and then we multiply this result by 3 to get 15.

  3/5   of 25 g = 15 g.

Here is an example of finding a fraction of an amount of money . We have the question   4/5   of £30.

example of finding a fraction of an amount 4/5 of 30

We first divide the amount by the denominator on the bottom of the fraction.

30 ÷ 5 = 6

We then multiply this result by the numerator.

6 × 4 = 24

bar model method for finding a fraction of an amount

4/5   of £30 = £24.

example of how to work out a fraction of an amount using the bar model method

Here is another example of finding a fraction of an amount.

In this question we are finding a fraction of a length. What is   2/7   of 56 cm?

First, divide the amount by the denominator. 56 ÷ 7 = 8.

Secondly, multiply this result by the numerator. 8 × 2 = 16.

example of finding a fraction of a length

  2/7   of 56 cm = 16 cm.

Here is an example of finding a fraction of a volume.

What is   5/6   of 42 ml?

Firstly, divide the amount by the denominator. 42 ÷ 6 = 7.

Secondly, multiply this result by the numerator. 7 × 5 = 35.

example of finding a fraction of a volume

  5/6   of 42 ml = 35 ml.

Fractions of Amounts using the Bar Model

A bar model is simply a rectangle drawn to represent the total amount. To find a fraction of an amount using the bar model, simply divide the total bar into smaller rectangles of equal size and then shade in however many of these parts you need.

The denominator of the fraction is how many parts the bar model is split into.

The numerator of the fraction is how many parts of the bar model to be shaded.

Here are the steps for finding a fraction of an amount using a bar model.

  1. Draw a rectangular bar to represent the total amount.
  2. Divide this bar into the same number of equally sized parts as the denominator of the fraction.
  3. Write the value found by dividing the total by the denominator inside each part.
  4. Shade in as many of these parts as the numerator of the fraction.
  5. Multiply the number of parts shaded by the value of each part.

Here is an example of using the bar model to work out the fraction of an amount   2/3   of 18.

Firstly, a rectangular bar is drawn to represent the total. 18 is written inside the bar.

using the bar model method to find the fraction 2 thirds of 18

The next step is to divide the bar into the same number of parts as the denominator of the fraction.

The denominator is 3 so the bar model is divided into 3 equal parts.

18 ÷ 3 = 6, so we write 6 inside each part.

The next step is to shade in as many parts as there are in the numerator of the fraction.

The numerator is 2, so we shade in 2 parts.

the bar model method fo teaching fractions example: what are 2 thirds of 18?

The final step is to multiply the number of parts by the value of each part.

2 × 6 = 12 and so   2/3   of 18 = 12.

teaching fractions of amounts using the bar model method

The bar model method is used to introduce the written method for finding fractions of amounts. The bar model method allows the size of a fraction to be visualised, which can make the process of dividing by the denominator and multiplying by the numerator more understandable.

When teaching how to find fractions of amounts, it is best to start with finding unit fractions of an amount. This is because finding a unit fraction of an amount is a simple one-step division. Once this is understood, non-unit fractions of an amount can be found by multiplying the result by the numerator.

The bar model method is a visual way to introduce non-unit fractions as the numerator of the fraction is represented by the number of parts shown. It is best to show the bar model method before going straight into a written method, so that the conceptual understanding of what a fraction of an amount is is first understood.

How to Find an Improper Fraction of a Number

To find an improper fraction of a number, use the same method used to find a proper fraction of a number. Divide the number by the denominator and then multiply this by the numerator. When finding an improper fraction of a number, the answer will be bigger than the original number.

An improper fraction is simply a fraction that has a larger numerator on top than its denominator on the bottom. It behaves in exactly the same way as a proper fraction does.

For example, we will work out   5/2   of 10.

example of finding an improper fraction of a number

The steps for finding an improper fraction of a number are:

  1. Divide the number by the denominator.
  2. Multiply this result by the numerator.

10 ÷ 2 = 5 and then 5 × 5 = 25.

how to find an improper fraction of a number

5/2   of 10 is 25. We can see that finding an improper fraction of a number makes the original number get larger.

This is the opposite of finding a proper fraction of a number, which makes the original number get smaller.

How to Find a Mixed Number Fraction of a Number

To find a mixed number fraction of a number, first convert the mixed fraction into an improper fraction. Then divide the number by the denominator of the fraction and multiply this result by the numerator. Finding a mixed fraction of a number will make the original number larger.

For example, here is the question of 3   1/2   of 4.

example question multiplying a mixed number by a whole number

A mixed number is a combination of a whole number and a fraction. 3   1/2   is a mixed number because it is made up of the whole number 3 and the fraction   1/2  .

The first step is to convert the mixed number into an improper fraction.

To convert a mixed number into an improper fraction:

  • Multiply the denominator and the whole number together.
  • Add the numerator of the fraction to this result to get the numerator of the improper fraction.
  • Keep the denominator the same.

how to convert a mixed number to an improper fraction example of 3 and a half to 7 over 2

We keep the denominator as 2.

We multiply the denominator of 2 by the whole number of 3 to get 6.

We add the numerator of 1 to this to get 7, which is the numerator of our answer.

3   1/2   =   7/2  .

Now that we have converted the mixed number to an improper fraction, we can find the fraction of the number.

finding an improper fraction of an amount

We divide by the denominator and then multiply by the numerator.

4 ÷ 2 = 2 and then 2 × 7 = 14.

3   1/2   of 4 = 14.

Again we can see that finding a mixed number fraction of a number made it larger.

Alternatively, to multiply a mixed number by a whole number, simply multiply by the whole number part and the fraction part separately before adding the results together.

3   1/2   is made up of 3 and   1/2  .

We can multiply 4 by 3 and then by   1/2  .

4 × 3 = 12 and 4 ×   1/2   = 2.

12 + 2 = 14, which is the same answer as using the other method.

How to Find a Fraction of a Decimal Number

To find a fraction of a decimal number, divide the decimal by the denominator and multiply this result by the numerator.

For example, here is the decimal number of 3.6. We will find   2/3   of 3.6.

example of finding a fraction of a decimal number

To find a fraction of a decimal:

  • Divide the decimal by the denominator.
  • Multiply this result by the numerator.

how to find a fraction of a decimal number

3.6 ÷ 3 = 1.2 and then 1.2 × 2 = 2.4

  2/3   of 3.6 = 2.4.

How to Find a Fraction of a Fraction

To find a fraction of a fraction, multiply the numerators together to find the numerator of the answer and then multiply the denominators together to find the denominator of the answer. Finding a fraction of a fraction is the same as multiplying fractions.

In maths, the word 'of' can mean to multiply.

Finding a fraction of a fraction simply means to multiply the first fraction by the second fraction.

For example, here is   2/5   of   3/4  .

We replace the word 'of' with a multiplication sign. We write   2/5   of   3/4   as   2/5   ×   3/4  .

finding a fraction of a fraction question

To find a fraction of a fraction, the first step is to multiply the numerators together to find the numerator of the answer.

The next step is to multiply the denominators together to find the denominator of the answer.

multiplying fractions together example

Multiplying the numerators: 2 × 3 = 6.

Multiplying the denominators: 5 × 4 = 20.

  2/5   ×   3/4   =   6/20  .

We then simplify the fraction if possible. Both 6 and 20 are even and can be divided by 2.

  6/20   =   3/10  .

Therefore   2/5   of   3/4   =   3/10  .

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Now try our lesson on Adding Fractions with Common Denominators where we learn how to add two fractions that have the same denominator as each other.

Unit Fractions of Amounts

Unit Fractions of Amounts

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Example of How to Find Unit Fractions of an Amount

  • A unit fraction is a fraction that has a 1 on top.
  • A unit fraction has a
    numeratorThe number on the top of a fraction, above the dividing line.
    of 1.
  • The
    denominatorThe number on the bottom of a fraction, below the dividing line.
    on the bottom of the fraction can be any other whole number.
  • To find a unit fraction of an amount, divide the amount by the denominator on the bottom of the fraction.
  • The denominator tells us how many equal parts to divide our amount into.
  • We divide 18 into three parts to find   1 / 3   of 18.
  • 18 ÷ 3 = 6.
  • One third of 18 is 6.
A unit fraction has a numerator of 1.

To find a unit fraction of an amount, divide the amount by the denominator.

Examples of Unit Fractions

Below are some examples of different unit fractions.

poster of unit fraction examples

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example of calculating unit fractions of amounts

  • To calculate a unit fraction of an amount, divide the amount by the
    denominatorThe number on the bottom of a fraction, below the dividing line.
    of the fraction.
  • The denominator is the number on the bottom of our fraction, which is 5.
  • 1 / 5   is said as 'one fifth'.
  • To find one fifth of an amount, divide it by 5.
  • 50 ÷ 5 = 10.
  • Therefore,   1 / 5   of 50
    gramsA gram is a measurement of weight. An egg is about 50 grams.
    is 10 grams.

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Unit Fractions of Amounts: Interactive Questions

Unit Fractions Worksheets and Answers

Unit Fractions

What are Unit Fractions?

A unit fraction is a fraction that has a numerator of 1. This means that the number on the top of a unit fraction must be a 1. The denominator on the bottom of a unit fraction can be any other whole number.

Unit fractions are called this because they have a numerator of 1. Unit means 1. The name of unit fraction tells us that this fraction must have a numerator that is equal to 1.

The first examples of unit fractions are:

Unit Fraction Name
1/2 One half
1/3 One third
1/4 One quarter
1/5 One fifth
1/6 One sixth

After the first few unit fractions shown above, the rest of the unit fractions are pronounced by saying "one" then the number then "th". For example,   1/10   is pronounced as "one tenth".

Here is a poster showing the size of unit fractions and pictures of unit fractions.

poster of unit fractions with pictures

Unit fractions always have a numerator of 1. The number on the bottom can be any other whole number.

The numerator of a fraction is the number on the top of it. The numerator tells us how many parts we have.

The denominator of a fraction is the number on the bottom of it. The denominator tells us how many parts there are in total.

One quarter is an example of a unit fraction because it has a 1 on top as its numerator.

a unit fraction example of one quarter

The denominator of one quarter is a 4, which means that the shape is divided into 4 parts.

We can see that the larger the denominator of a unit fraction, the more parts we have divided the amount into and the smaller the size of the fraction.

A unit fraction must have a numerator of 1. A fraction that is not a unit fraction is called a non-unit fraction. Non-unit fractions have a numerator that is larger than 1.

How to Find Unit Fractions of Amounts

To find a unit fraction of an amount, divide the amount by the denominator of the fraction. For example to find   1/3   of 18, divide 18 by 3. 18 ÷ 3 = 6 and so, one third of 18 is 6.

  1/3   is a unit fraction with a denominator of 3. To find   1/3   of 18, divide 18 by 3.

unit fraction example finding one third of 18

Unit fractions can be represented using a bar model. The full bar represents the total amount and this can be divided up into equal parts to represent the unit fractions.

Here the whole bar is worth 18 and we can divide it into 3 equal parts to find one third.

example of finding a unit fraction of an amount. one third of 18.

18 ÷ 3 = 6 and so,   1/3   of 18 = 6.

We can work this out by thinking, "What number do I need to multiply 3 by to get 18?"

3 × 6 = 18 and so one third of 18 is 6.

Here is another example of finding a unit fraction of a number.

In this problem we are asked to find   1/2   of 10.

one half of 10 is 5

To find a unit fraction of a number, divide the number by the denominator of the fraction.

To find   1/2   of 10, divide 10 by 2.

example of finding a unit fraction of a number. one half of 10 is 5

10 ÷ 2 = 5 and so, one half of 10 is 5.

Here is another example of calculating a unit fraction of an amount.

In this unit fraction problem, we have to find   1/4   of £44.

calculating the unit fraction of an amount, example of one quarter of 44

If there are units in a unit fraction problem, simply ignore them, do the calculation and then put them back in at the end.

We divide by the denominator of the fraction. The denominator is 4.

finding a unit fraction of an amount. one quarter of 44 pounds.

44 ÷ 4 = 11 and so, £44 ÷ 4 = £11.

One quarter of £44 is £11.

Here is an example of finding the unit fraction   1/3   of 36 m.

To find a unit fraction of an amount, divide by the denominator. The denominator of one third is 3. To find one third, divide by 3.

finding the unit fraction one third of 36 metres

36 ÷ 3 = 12 and so, 36 m ÷ 3 = 12 m. One third of 36 metres is 12 metres.

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Now try our lesson How to Find Fractions of Amounts, where we learn how to find non-unit fractions of amounts.

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