How to Find Simple Percentages of a Number

How to Find Simple Percentages of a Number

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rules for finding simple percentages poster

Rules for Finding Basic Percentages

poster of rules for finding basic percentages

  • To find 1%, divide the number by 100.
  • To find 5%, divide the number by 20 or find half of 10%.
  • To find 10%, divide the number by 10.
  • To find 20%, divide the number by 5 or find 10% and double it.
  • To find 25%, divide the number by 4.
  • To find 33.̄3%, divide the number by 3.
  • To find 50%, divide the number by 2.
  • To find 75%, divide the number by 4 and then multiply by 3.
Find simple percentages of a number by dividing using the rules shown above.

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example of finding a simple percentage of an amount

  • We want to find 20% of 40.
  • To find 20% of a number, divide the number by 5 or find 10% and double it.
  • 40 ÷ 5 = 8 and so, 20% of 40 = 8.
  • Alternatively, we can find 10% and double it.
  • To find 10% of 40, divide it by 10.
  • 10% of 40 = 4.
  • We double 10% to find that 20% = 8.

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Calculating Simple Percentages (1%, 5%, 20% and 75%): Interactive Activity

1%, 5%, 20% and 75% of an Amount: Interactive Questions

Calculating Simple Percentages (10%, 25% and 50%) : Interactive Activity

Finding 10%, 25% and 50% of an Amount: Interactive Questions

Calculating Multiples of 10% of an Amount

Multiples of 10 Percent: Interactive Questions

Simple Percentages as Fractions Worksheets and Answers

Simple Fractions of Amounts Worksheets and Answers

Finding Multiples of 10% of a Number Worksheets and Answers

Simple Percentages of Amounts

Rules for Finding Simple Percentages of a Number

The rules for finding simple percentages of a number are shown in the following table:

Percentage Rule
1% ÷ 100
5% ÷ 20
10% ÷ 10
20% ÷ 5
25% ÷ 4
33.̄3% ÷ 100
50% ÷ 2
75% ÷ 4 then × 3

To find the percentages of a number shown in the table above, simply divide the number using the rules provided.

Simple percentages are percentages of amounts that can be found with a simple division or multiplication. They do not require any addition of any smaller percentages.

For example, 50% is a simple percentage because we simply divide by 2 to find it. 31% is not a simple percentage we would need to calculate 30% and 1% and add them together.

Here is a poster showing how to calculate basic percentages.

poster of how to find percentages of amounts

To introduce percentages, it is best to start with simple percentages and showing them as a fraction out of 100. For example, 50% means 50 out of 100, which is half. To find 50% of a number, simply half it.

Before looking at larger percentages, it is best to introduce basic percentages with a visual guide to how large they are. To teach how large a percentage is, you can show the percentage as a fraction of 100 squares.

percentages to fractions list

Start by introducing the following percentages first: 10%, 20%, 25%, 50%, 75% and 100%.

How to Calculate 1% of a Number

To calculate 1% of a number, divide the number by 100. To divide by 100, move the decimal point two places left. For example, 1% of 135.6 = 1.356.

1% means 1 out of 100. 1% is the same as the fraction   1/100  .

To teach 1%, we can show 1 square shaded out of 100 squares.

diagram showing 1% for teaching

1% means   1/100   and so, finding 1% of a number means to find   1/100   of that number.

To find 1% of a number without a calculator, divide the number by 100. The easiest way to do this is to move the decimal point 2 places to the left.

Here are some examples of finding 1%,

Question Answer
1% of 300 3
1% of 150 1.5
1% of 25 0.25
1% of 8 0.08
1% of 3.6 0.036
1% of 0.205 0.00205

To find 1% of a number with a calculator, divide the number by 100. You can also multiply the number by 0.01.

1% is a basic percentage because it can be found with one simple division. 1% is a very useful percentage to know how to find because you can use it to find any larger, whole number percentage of a number. Simply multiply the percentage required by the value of 1%.

How to Calculate 5% of a Number

To find 5% of a number, divide the number by 20. This can be done by dividing the number by 10 and then halving it. For example, 5% of 40 = 2.

5% means 5 out of 100. 5% is the same as the fraction   5/100  , which can be simplified to   1/20  .

5% is a twentieth of the whole number. diagram showing 5% for teaching

5% means   1/20   and so, finding 5% of a number means to find   1/20   of that number.

To find 5% of a number without a calculator, divide the number by 20. The easiest way to do this is to divide by 10 and then halve the result.

Here are some examples of finding 5%,

Question Answer
5% of 200 10
5% of 60 3
5% of 30 1.5
5% of 8 0.4
5% of 1.6 0.08
5% of 0.402 0.0201

To find 5% of a number with a calculator, divide the number by 20. You can also multiply the number by 0.05.

Finding 5% is best to introduce after you have already learnt how to find 10%.

How to Calculate 10% of a Number

To calculate 10% of a number, divide the number by 10. The easiest way to do this is to move the decimal point one place to the left. For example, 10% of 14.5 = 1.45.

10% means 10 out of 100. 10% is the same as the fraction   10/100  , which simplfies to   1/10  .

To teach 10%, we can show 10 squares shaded out of 100 squares.

teaching and introducing 10% as a fraction

10% means   1/10   and so, finding 10% of a number means to find   1/10   of that number.

To find 10% of a number without a calculator, divide the number by 10. The easiest way to do this is to move the decimal point 1 place to the left.

Here are some examples of finding 10%,

Question Answer
10% of 1200 120
10% of 600 60
10% of 50 5
10% of 9 0.9
10% of 5.3 0.53
10% of 0.105 0.0105

To find 10% of a number with a calculator, divide the number by 10. You can also multiply the number by 0.1.

10% is a basic percentage because it can be found with one simple division. 10% is a very useful percentage to know how to find because we can easily multiply 10% to find other multiples of 10%, such as 20%, 30% etc.

Multiples of 10% of a Number

To find multiples of 10% of a number, use these rules:

Percentage Rule
10% ÷ 10
20% ÷ 10 then × 2
30% ÷ 10 then × 3
40% ÷ 10 then × 4
50% ÷ 10 then × 5
60% ÷ 10 then × 6
70% ÷ 10 then × 7
80% ÷ 10 then × 8
90% ÷ 10 then × 9

Here is a poster showing how to find all of the multiples of 10% of a number.

poster showing how to find multiples of 10% of a number

For example, to find 30% of 50, divide 50 by 10 to find 10% and then multiply this by 3 to get 30%.

example of finding 30% of 50

To find 10% of 50, divide it by 10. 10% of 50 = 5.

Now that we have 10%, we simply multiply it by 3 to find 30%. 30% of 50 = 15.

how to find 30% of a number example of 30% of 50

Here is another example of finding a multiple of 10 percent. What is 40% of 70 grams?

To find 40% of a number, divide it by 10 to find 10% and then multiply this by 4.

how to calculate 40% of an amount

10% of 70 grams = 7 grams.

To find 40%, we multiply 10% by 4. 40% of 70 grams = 28 grams.

working out 40% of the amount 70 grams

Here we will find 80% of 120.

how to calculate 80% of a number

To calculate 80% of a number, divide the number by 10 to get 10% and then multiply this by 8.

10% of 120 = 12.

80% is 10% multiplied by 8. 80% = 96, therefore 80% of 120 = 96.

how to find 80% of a number 120

How to Calculate 20% of a Number

To calculate 20% of a number, divide it by 5. Alternatively, divide the number by 10 and then double it. For example, 20% of 30 = 6.

20% means 20 out of 100. 20% is the same as the fraction   20/100  , which can be simplified to   1/5  .

20% is a fifth of the whole number. diagram for teaching and introducing 20%

20% means   1/5   and so, finding 20% of a number means to find   1/5   of that number.

To find 20% of a number without a calculator, divide the number by 5. Alternatively, divide the number by 10 and then double it.

Here are some examples of finding 20%,

Question Answer
20% of 400 80
20% of 20 4
20% of 70 14
20% of 5 1
20% of 6.1 1.22
20% of 0.303 0.0606

To find 20% of a number with a calculator, divide the number by 5. You can also multiply the number by 0.2.

How to Calculate 33   1/3   % of a Number

To calculate 33   1/3   % of a number, divide it by 3.

3   1/3   is the same as 33.̄3%. To find 3   1/3   or 33.̄3%, divide the number by 3.

diagram for teaching that 33% is one third

33.̄3% means   1/3   and so, finding 33.̄3% of a number means to find   1/3   of that number.

To find 33.̄3% of a number without a calculator, divide the number by 3.

To find 33.̄3% of a number with a calculator, divide the number by 3. You can also multiply the number by 0.̄3.

How to Calculate 50% of a Number

To calculate 50% of a number, divide the number by 2. For example, 50% of 20 = 10.

50% means 50 out of 100. 50% is the same as the fraction   50/100  , which simplfies to   1/2  .

To teach 50%, we can show 50 squares shaded out of 100 squares.

diagram for teaching 50 percent

50% means   1/2   and so, finding 50% of a number means to find   1/2   of that number.

To find 50% of a number without a calculator, divide the number by 2. To divide an odd number by 2, subtract one, half it and then add 0.5

Here are some examples of finding 50%,

Question Answer
50% of 800 400
50% of 300 150
50% of 20 10
50% of 7 3.5
50% of 2.6 1.3
50% of 0.804 0.402

To find 50% of a number with a calculator, divide the number by 2. You can also multiply the number by 0.5.

How to Calculate 75% of a Number

To calculate 75% of a number, divide the number by 4 and then multiply this result by 3. For example 75% of 20 = 15.

75% means 75 out of 100. 75% is the same as the fraction   75/100  , which simplfies to   3/4  .

75% is three quarters of an amount.

To teach 75%, we can show 75 squares shaded out of 100 squares. It is helpful to shade the squares in the four corners as shown.

diagram for explaining 75 percent as three quarters, 75% = 3/4

75% means   3/4   and so, finding 75% of a number means to find   3/4   of that number.

To find 75% of a number without a calculator, divide the number by 4 and then multiply by 3.

Here are some examples of finding 75%,

Question Answer
75% of 800 600
75% of 300 225
75% of 60 45
75% of 4 3
75% of 6.8 5.1
75% of 0.334 0.2505

To find 75% of a number with a calculator, divide the number by 4 and then multiply by 3. You can also multiply the number by 0.75.

What is 100% of a Number?

100% of a number is the whole of the number. 100% means one whole and so, 100% of a number is simply the number itself.

100% means 100 out of 100. 100% is the same as the fraction   100/100  , which simplfies to 1 whole.

We can see in this diagram that 100% shows all 100 squares shaded in.

what is 100%? diagram explaining 100%.

To find 100% of something simply means to find the whole amount of it. For example, 100% of 25 = 25.

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Now try our lesson on How to Calculate Percentages of Numbers where we learn how to find any percentage of a number.