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Before learning the numerals 11 to 20 first watch our lesson on Roman Numerals 1 to 10.
We can add up to three of the same numeral together in a row to make larger numbers.
For example, two I numerals is two lots of one and makes a total of 2.
2 is written as II in Roman numerals.
We can write III as 3. This is because we have three I numerals. 1 + 1 + 1 = 3.
We cannot write 4 as IIII because it uses four I numerals. The most we are allowed to use together is three.
Instead we write 4 as IV, which is an I before a V, which means 1 before 5.
We can count on from 5 to make larger numbers.
VI means V plus I, which means 5 plus 1.
VI is 6 in Roman numerals.
Similarly 7 is written as VII because V + I + I means 5 + 1 + 1.
8 is VIII because V + I + I + I means 5 + 1 + 1 + 1.
Again we can’t write 9 as VIIII because it uses four of the same numeral at once. We are only allowed to write three of the same numeral at once.
Instead, 9 is written as 1 before 10. We write IX because I is 1 and X is 10.
Here are the Roman numerals to 10. Please visit our lesson on Roman numerals 1 to 10 for our video lesson. When teaching the Roman numerals to 20, we recommend first learning these numerals to 10.
11 is ten more than 1, 12 is ten more than 2, 13 is ten more than 3 and so on.
The numbers 11 to 20 are simply 10 more than the numbers 1 to 10.
To write the Roman numerals to 20, simply add the numerals for the numbers 1 to 10 to the numeral X.
X is worth ten and when writing any numerals after this, it will add ten to those numerals.
Here are the Roman numerals 11 to 20 formed by writing an X numeral in front of the numeral that is 10 less in value.
For example, 11 is ten more than 1.
The numeral for 1 is I.
Therefore to write 11, we write an X and then the numeral for 1.
11 is written as XI in Roman numerals.
XI means X + I, which is 10 + 1.
10 + 1 = 11.
Similarly, 15 is ten more than 5.
Therefore to write 15, we write an X and then the numeral for 5.
The numeral for 5 is V.
15 is written as XV in Roman numerals.
XV is X + V, which means 10 + 5.
It is important to note that we always need to write the larger numerals first when adding Roman numerals.
We have to write XV in that order because X is worth 10 and V is only worth 5.
We cannot write V then X as it breaks this rule. We simply write an X and then the smaller value numerals.
Here we have XVII.
This means X + V + I + I, which means 10 + 5 + 1 + 1.
XVII are the Roman numerals for 17.
VII is 7 and so, if we remember how to write 7, then we simply write an X in front to make 17.
Remember that 4 is written as IV because we can’t use four I numerals.
IV is one before five, which is four.
XIV is simply IV with an X numeral before it.
XIV is X + IV, which means 10 + 4.
Remember that we only add Roman numerals when they are decreasing in size.
I is less than V and so we do not add IV to make 6.
Instead we subtract I from V to make 4. It is easiest to read IV as 1 before 5.
6 is 1 after five, which is written as VI.
Here is the final list of the Roman numerals for 11 to 20. We can see the numeral X highlighted in blue, with the numerals following shown in red.
Now try our lesson on Rounding Off to the Nearest 10 on a Number Line where we learn how to round numbers to the nearest ten.
We can add these numerals together up to 3 times in a row to write other numbers.
Roman numerals are a different system of writing numbers. Instead of using the digits of 1, 2, 3, 4, 5, 6, 7, 8, 9 or 0, Roman numerals use the capital letters of the alphabet: I, V, X, L, C, D and M.
To write larger numbers, numerals can be added by writing them next each other.
Roman numerals to 10 are written using the three numerals of I, V and X.
I is the first Roman numeral. I is the roman numeral for 1.
We can add two ones together to make 2. We add numerals by writing them next to each other.
II is made from two I numerals. II means 1 + 1.
II is worth 2.
2 is written as II in Roman numerals.
We can add up to three of each numeral.
We can add three I numerals to make III.
III means 1 + 1 + 1.
3 is written as III in Roman numerals.
We can only use three Roman numerals together at once.
We have already used three I numerals to make III.
To make larger numbers, we need to use the numeral of V.
V is the Roman numeral for 5.
So far we have:
I = 1
II = 2
III = 3
V = 5
4 is written a little differently in Roman numerals.
We are not supposed to write more than 3 of the same numeral together. We can’t write IIII for 4 because this contains more than three I numerals.
Instead we use the fact that 4 is one less than 5.
We can write 4 as one less than five.
We write 4 as one before five. 1 is written as ‘I’ and 5 is written as ‘V’.
To write 1 before 5, we write I before V.
4 is written as IV in Roman numerals.
Here is a chart showing the Roman numerals to 5.
We have I for 1, II for 2, III for 3, IV for 4 and V for 5.
To make the numbers larger than 5 using Roman numerals, we count on in ones from five.
5 is written using the numeral of V.
We can count on from five using the numeral of I. We can use up to three I numerals at once.
6 is one more than five. To write one more than five, we write an I after a V.
6 is Roman numerals is VI. VI is V + I, which is 5 + 1.
7 is two more than five. To write two more than five, we write two I numerals after a V numeral.
7 in Roman numerals is VII. VII is V + I + I, which is 5 + 1 + 1.
8 is three more than five. To write three more than five, we write three I numerals after the V numeral.
8 in Roman numerals is VIII. VIII is V + I + I + I, which is 5 + 1 + 1 + 1.
The Roman numeral for 10 is X.
In the same way that we wrote 4 as IV, we write 9 as IX.
We cannot write VIIII for 9 because it would mean using four I numerals. We are only allowed to use three at most.
We write 9 in Roman numerals as IX, which is an I before an X. 1 before 10 is 9.
Both 4 and 9 are different to the other Roman numerals because they have an I before another numeral.
4 is one before 5 and so is written IV.
9 is one before 10 and so is written IX.
These are the only numbers in the list of Roman numerals to 10 that behave like this.
When teaching Roman numerals, 4 and 9 are most commonly written incorrectly.
Some students can think that IV is 1 + 5, rather than reading it as 1 before 5.
It is important to show the difference between 4 and 6.
4 is IV and 6 is VI. If a smaller numeral is written before a larger value numeral then we subtract the smaller numeral away from the larger numeral.
There is no Roman numeral for zero.
Now try our lesson on Roman Numerals to 20 where we learn how to read and write Roman numerals up to 20.
Insert a less-than or greater-than symbol which points at the smaller value side.
‘<' is the less-than symbol.
‘>’ is the greater-than symbol.
Each sign is chosen in a number sentence so that the symbol points to the side that has the smallest value.
Each symbol then opens up to the side that has the greatest value.
We can use a number line to decide which side of a number sentence has the greatest value.
When teaching comparing number size, a number line is useful to help visualise the size of each value.
Here are the multiples of 10 from 0 to 100 shown on a number line.
When comparing number sentences at KS1 and KS2 (up to fourth grade), most children will be expected to use greater-than or less-than symbols for numbers up to 100.
In this example we have a missing symbol between 30 + 10 and 80.
We first evaluate the addition sum on the left of the missing symbol problem.
30 + 10 = 40.
40 is less than 80 because it is further left on the number line.
We can use the less-than symbol ‘<' to write this mathematically.
We can think of the symbol like an arrow, pointing to the smaller value. We can also think of it as an open mouth opening up to the larger value.
We can write 40 < 80.
40 is the smaller number and so, the less-than symbol points at 40.
Because 40 < 80, we can also write 30 + 10 < 80.
Here is our next example of comparing number sentence values.
We have a missing symbol between 90 + 4 and 60.
We first work out the value of 90 + 4.
90 + 4 = 94, which is to the right of 60 on the number line.
This means that 94 is greater than 60.
We use the greater-than symbol, ‘>’ to write this comparison mathematically.
60 is smaller than 94 and so, the arrow will point at 64. The ‘mouth’ will open up to the larger value of 94.
We can write 94 > 60 to say that 94 is greater-than 60.
Because 94 > 60, we can also write 90 + 4 > 60.
In this next example of comparing a subtraction sentence we have a missing symbol between 15 and 20 – 2.
We first evaluate the subtraction of 20 – 2.
20 – 2 = 18, which is to the right of 15 on the number line.
18 is greater-than 15 and so the symbol opens to the 18 and points to the 15.
We can write 15 < 18 and so, 15 < 20 - 2.
In this next example we have a missing symbol between 12 + 14 and 26.
We first evaluate the addition of 12 + 14.
12 + 14 = 26, which is the same as on the other side of the number sentence.
12 + 14 is the same value as 26 and so, we use an equals sign ‘=’ to show this.
Now try our lesson on Rounding Off to the Nearest 10 on a Number Line where we learn how to round to the nearest 10.
These happens when you do not have the exact amount of money.
Money comes in certain values which are written on coins or notes. Because of this it is unlikely that you will always be carrying the exact amount of money needed to pay for something.
If this is the case then we need to pay more than the cost of the item and then get the extra money back.
The money given back is called change. Change is the difference between the cost of the item and the money given to pay for it.
In the example below we have four coins: three 10p coins and one 20p coin.
In total this is 50 pence.
We want to buy a spinning top for 30 pence.
We can pay for the spinning top with 30p from our 50 pence. We can pay using the three 10p coins.
In this example, we have 20p left. We were able to pay for it directly with the coins we had and so, we were not given change.
We started with 50 pence and spent 30 pence.
To see how much money we have remaining we subtract the cost of the item from the amount of money we started with.
50 – 30 = 20
We have 20 pence remaining after purchasing the toy.
Here is an example with four coins: three 10p coins and a 5p coin. We have 35p.
We want to buy a banana which costs 32 pence.
This time we cannot pay for the banana exactly. If we give three 10p coins, then we spend 30 pence and if we give the remaining 5p coin, we have paid 35 pence.
We give an amount greater than the cost of the banana and so we give 35 pence.
35 is 3 more than 32 and so, we have spent 3 pence too much.
To keep it fair, we are given this 3 pence back as change.
We are given a 1p and 2p coin, worth 3 pence.
In this example of giving change, we have 44 pence.
We want to buy a toy teddy bear which costs 43 pence.
We cannot spend exactly 43 pence and so we hand over all of the money.
44 pence is 1 pence more than 43 pence and so, we have spent 1p more than the cost of the bear.
We are given this 1p coin back as change.
Here we have a 50p coin and want to buy a toy car which costs 45 pence.
We can only hand over the 50p coin and wait to receive change.
We can work out the change by thinking ‘How much more than 45 is 50?’.
50 is 5 more than 45 and so, we receive 5p back as change.
In this next example we have a 50p coin and a 20p coin. We want to buy an apple which costs 63 pence.
50p plus 20p is a total of 70 pence.
We will need to pay with both coins and wait to receive change.
We can think ‘How much more than 63 is 70?’.
70 is 7 more than 63 and so, we receive 7 pence back as change.
7p can be made using a 5 pence coin and a 2 pence coin.
Now try our lesson on Counting US Coins: Dimes, Nickels, Pennies & Quarters where we learn about the different US coins.
The number before the ‘×’ sign tells us how many times we are adding the number after the ‘×’ sign.
The number before the multiplication sign tells us how many times we are adding the number that comes after the multiplication sign.
An example of multiplication is 5 × 3. This means 5 lots of 3 or 5 equal groups of 3. It means to add 3 five times.
5 × 3 means 3 + 3 + 3 + 3 + 3. Multiplication is the same as repeated addition.
Here are some more examples of multiplication as repeated addition.
Each flamingo has 2 legs.
We can see that 2 + 2 + 2 + 2 requires us to add 4 lots of 2. This is relatively long to write out and not a quick way to work out the total.
It is quicker to write 4 × 2. Also we know that 4 × 2 = 8 through memorising the times tables.
Multiplication is useful because it is a faster way to do repeated addition and it is easier to write. Learning times tables is important because it allows us to calculate repeated additions immediately and it is necessary for understanding further concepts such as algebra.
Here is an example of writing repeated addition as a multiplication.
Each box of eggs contains 6 eggs.
Here are 3 boxes of eggs.
To find the total number of eggs in the three boxes, we do an addition.
We have 6 + 6 + 6 in total. We have 3 sixes added together.
We have 3 lots of 6.
We can write this as 3 × 6.
From our times tables, we should know that 3 × 6 = 18.
There are 18 eggs in total.
Here is another example of multiplication as repeated addition.
Each bicycle has 2 wheels.
Here are 4 bicycles.
To find the total number of wheels on 4 bicycles, we will add the number of wheels on each bike to make a total.
We have 2 + 2 + 2 + 2.
We have 4 lots of 2.
We can write this repeated addition as 4 × 2.
Here is another example of multiplication as repeated addition.
Each horse has 4 legs.
We will find the number of legs on 5 horses.
We have the repeated addition of 4 + 4 + 4 + 4 + 4.
We have 5 lots of 4.
We ca write this as 5 × 4.
From our times tables, 5 × 4 = 20.
There are 20 legs on 5 horses.
Here is an example where there are 3 cubes in each set.
We have 5 sets of cubes.
In total we have 3 + 3 + 3 + 3 + 3.
We have 5 equal groups of 3.
We can write this as 5 × 3.
From our times tables we know that 5 × 3 = 15.
There are 15 cubes in total.
Now try our lesson on Order of Multiplication where we learn rules about the order of multiplication.
Each shape is placed into the box that is in line with its properties.
The shapes are placed inside the circles which represent the properties that the shape has.
It belongs in the right circle but not the left circle.
Sorting shapes by their attributes is a skill that is learnt at late KS1/ early KS2 (first to third grade) after learning the names and properties of common shapes.
We can list the properties of shapes using a table. There are many shape properties and many shapes and we will look at some in this example.
We will first sort these shapes to decide whether they contain straight sides.
We will now count the corners of these shapes to see if they have more than 3 corners.
Remember we need more than 3 corners to tick the shapes that have this property. When teaching sorting shapes, it is a common mistake to include shapes that have exactly 3 corners, which is not correct.
3 corners is not the same as more than 3 corners.
We will now sort the shapes by whether they contain parallel sides.
Parallel sides are sides that face in exactly the same direction.
We will now sort the shapes by whether they contain a right angle.
A right angle is exactly 90 degrees. It looks like a ‘capital L’ shape.
Shapes are most commonly sorted using both a Venn diagram or a Carroll diagram. A Carroll diagram is different from a Venn diagram in that in a Carroll diagram objects are put into a table, whereas on a Venn Diagram objects are put into circles. On a Venn diagram, each circle is a different property and each object can be in more than one circle. However, on a Carroll diagram, the object can only go in one particular grid, in line with two of its properties.
A Carroll diagram is a table that can be used for sorting shapes by their attributes. The shapes will be placed inside the table in line with the properties in the rows and columns that describe it.
To sort shapes using a Carroll Diagram use these steps:
Here is an example of sorting shapes with a Carroll diagram. We have an isosceles triangle. It has 3 corners and its two sloping sides are a different length to its base side.
The triangle can only go in one of the four boxes shown in the Carroll diagram.
We first read the column properties. We have the choice of ‘4 corners or less’ or ‘more than 4 corners’.
The triangle has 3 corners which is ‘4 corners or less’. It needs to be sorted into the left column.
We now need to decide if it belongs in the top-left box or the bottom-left box.
We have a choice of ‘sides the same length’ or ‘sides of different lengths’.
Even though this triangle has 2 sides that are the same length, this is not enough to say that every side is the same length. The base side is smaller than the other two.
We must sort the triangle into the row for the property ‘sides of different lengths’.
We place the shape in the box that lines up with the properties that the shape has. It needs to go in the left column because it has ‘4 corners or less’ and it needs to go in the bottom row because it has ‘sides of different lengths’.
The isosceles triangle is sorted into the bottom-left box of the Carroll diagram.
We will now arrange the rest of the shapes in the Carroll diagram.
Here is another example of sorting shapes on a Carroll diagram.
In the two columns, we are sorting the shapes to decide if the sides are curved or straight.
To sort shapes using a Venn Diagram use these steps:
Here is an example of sorting a shape using a Venn diagram.
We have two circles and we will decide where to place this square.
The left circle is for shapes that contain a right angle.
The right circle is for shapes in which all of the sides are the same length.
We have a choice of sorting the square into the following positions on the diagram:
All of the angles on a square are 90 degree right angles. Therefore it does contain a right angle.
Because the shape contains a right angle, it must be placed somewhere inside the left circle.
All of the sides of a square are the same size.
Because all of its sides are the same size, it must be placed somewhere inside the right circle.
The square contains both properties represented by both circles and so, it needs to be placed inside both circles.
The square must be placed in the middle zone, where the two circles of the Venn diagram overlap.
We will now sort the remaining shapes on the Venn diagram.
Here is another example of sorting shapes on a Venn diagram.
This time the left circle is for shapes with more than 3 sides and the right circle is for shapes that contain a parallel set of sides.
Sorting Shapes on a Venn Diagram
A Venn diagram is an area which contains circular zones, which represent mathematical properties. To sort the shapes using a Venn diagram, we place the shapes inside the circles which represent the properties that the shape has.
Now try our lesson on Names of 3D Shapes where we learn the names of various common 3D shapes.
Start by adding the largest value coins.
It helps to have a list of the other coins that can be chosen and to write down these values when you can make them.
Here is an example of finding an equivalent amount of money to the amount shown.
We have: two 10p coins, a 5p coin and two 1p coins.
We start by adding the coins with the largest value. We will add the two 10p coins.
Two 10p coins are worth 20p. There is a 20 pence coin and so we will write this down.
The 5p coin cannot be added to two 1p coins to make a new coin. This is because there is no 6p or 7p coin.
We keep the 5p coin as a 5p coin.
The remaining two 1p coins can be added to make 2p. There is a 2p coin which can be used instead of two 1p coins.
The total of the money is 27 pence.
27 pence can be made from the first combination of money: two 10p coins, one 5p coin and two 1p coins.
27 pence can also be made from the new combination of coins: one 20p coin, one 5p coin and one 2p coin.
It is possible to make this amount of money in many other ways. For example we could simply have twenty-seven 1p coins.
In this lesson we will be looking to add coins together to make the amount with the least amount of coins.
In this example we have the following collection of coins:
Six 5p coins and three 1p coins.
We start by adding up the largest value coins. We will start by adding the 5p coins.
We cannot make 50p because six 5p coins added together makes 30p.
We will try and make 20p. This is the same as four 5p coins added together.
We write down 20p now that we have counted four of the six 5p coins.
There are two 5p coins left, which can make 10p.
The three 1p coins make 3p in total but there is not a 3 pence coin. We can use two of the 1p coins to make a 2p coin and then leave the final third 1 pence coin as a 1p.
The total of this amount of money is 33 pence.
33 pence can also be made from a 20p, a 10p, a 2p and a 1p coin.
The 20p is the same value as the four 5p coins, the 10p is the same value as the other two 5p coins and the 2p plus the 1p are the same as three 1p coins.
In this example, we have the following coins:
Two 20p coins, one 10p coin, two 2p coins and a 1p coin.
We will start by adding the largest value coins.
We can add two 20p coins to make 40 pence. However there is no 40p coin.
40p is only 10p less than 50p and we have a 10p coin.
20p plus 20p plus 10p is the same as 50p.
We can write down 50p.
We can add the two 2p coins to make 4p and again, there is no 4p coin. We can add the 1p coin to this amount to make 5p.
The two 2p coins plus the 1p coin can be replaced with a 5p coin.
The total of the money is 55 pence.
Instead of using the original combination of coins, we can also make 55p from a single 50p coin and a single 5p coin.
In this example we have three 10p coins, two 5p coins and three 2p coins.
We start by adding the largest value coins to try to make another coin.
If we add the three 10p coins, we have 30 pence. There is no 30 pence coin.
Even if we add the two 5p coins to this amount, we would only have 40 pence. There is no 40 pence coin. Because we cannot make the 50p coin with this money, we will try to make the next value coin, 20p.
Instead, two 10p coins can be used to make 20p.
The remaining 10p plus the two 5p coins can be used to make another 20p coin.
The three 2p coins add to make 6 pence. There is no 6p coin.
Instead this value of 6p can be made from a 5p coin plus a 1p coin.
The amount of 46 pence can be made from two 20p coins, one 5p coin and one 1p coin.
Now try our lesson on Counting US Coins: Dimes, Nickels, Pennies & Quarters where we learn the values of American coins.
Subtraction facts to 20 are subtraction sums in which we are subtracting from 20.
To subtract from 20 we should know the number bonds to 20. The number bonds to 20 are pairs of numbers that add to make 20.
To learn the number bonds to 20, start with the number bonds to 10 and add a ten to one of the numbers in each pair. We do this by adding a ‘1’ tens digit in front of one of the numbers.
Here is our first example of subtracting from 20.
We have 20 – 8.
From the number bonds to 10 we know that 8 + 2 = 10.
8 + 2 = 10 and so, 8 + 12 = 20.
Because 8 + 12 = 20, 20 – 8 = 12.
The missing number in this subtraction fact is 12.
To subtract a number from 20, we can see how many more we add to this number to make 20. To subtract a single digit number from 20, the answer will be 10 more than this number’s number bond to 10.
For example, we subtracted 8 from 20 and so we add 10 to the number that adds to 8 to make 10. We add 10 to 2 to get the answer of 12.
Here is another example of subtracting from 20. We have 20 – 6.
Using the number bonds to 10, 6 + 4 = 10.
Therefore 6 + 14 = 20.
And so 20 – 6 = 14.
The missing number is 14, which is 10 more than 6’s number bond to ten.
In this example we will subtract a 2-digit number from 20. We have 20 – 12.
We can see that 12 ends in a ‘2’.
2 + 8 = 10
And so, 12 + 8 = 20.
The answer to 20 – 12 is 8.
To subtract a 2-digit number from 20, the answer will be the number bond to ten of the number that is 10 less than the number being subtracted.
In this example we are subtracting 12 and so the answer is the number bond to ten that goes with 2.
8 is the answer.
In this example we are finding the missing number in the middle of a subtraction fact to 20.
20 – something = 5.
The missing number is the number that can be added to 5 to make 20.
5 + 5 = 10 and so,
5 + 15 = 20.
The missing number is 10 more than the number bond to ten of the answer.
Here is an example of 20 – something = 3.
We start by looking at the answer to the subtraction, which is 3.
3 + 7 = 10 and so,
3 + 17 = 20.
Therefore 20 – 17 = 3.
The missing number is 17, which is ten more than 3’s number bond to ten.
Now try our lesson on Addition using the Compensation Strategy where we learn how to add numbers using the compensation strategy.
Cross the coins off if we cannot add another without making a value larger than we need.
To add coins to make a particular value, start by looking at the largest value coins. If the coin’s value is larger than the value being made, cross off the coin. Continue to add coins, crossing them off if adding them to the total takes the total over the value needed.
Here is an example of making a particular value.
Find a combination of coins that add to make 52 pence.
We start with the largest value coin, 50 pence.
50p is less than 52p and so, we can take one 50p coin.
If we add another 50p coin, we have too much. We need 2 more pence to get to 52p.
We can make 52p using a 50 pence coin plus a 2 pence coin.
In this example we will make 61 pence.
We can start with 50 pence, which is less than 61p.
If we add another 50p, we will have more than 61p and so, we cross it off.
If we add a 20 pence to the 50p coin, we have 70p, which is more than 61 pence. We do not take a 20 pence coin.
If we add a 10 pence coin to the 50p coin, we have 60p.
We need 1 more pence to make 61p.
61 pence can be made from a 50 pence coin, a 10 pence coin plus a 1 pence coin.
In this example, we will look at how to make a value of 27 pence using coins.
50 pence is the largest pence coin and it is too much. It is larger than 27 pence. We cross it off immediately.
We can take one 20 pence coin.
If we add a 10 pence coin to the 20 pence coin, we have 30 pence. This is too much and so, we cross off the 10 pence coin.
We can take one 5 pence coin.
20 + 5 = 25. We have 25 pence so far.
We can take a 2 pence coin to make 27 pence.
In this example we will make 36 pence.
50 pence is already too large and so, we cross it off.
We can take a 20 pence.
Another 20 pence would make 40 pence and this is too large. We cross off the 20 pence coin now.
We can instead add a 10 pence to the 20 pence coin. This makes 30 pence.
Adding another 10 pence to 30 pence would make 40 pence and so, we do not add another 10p coin.
We can add a 5p coin to make 35 pence.
We can finally add a 1 pence coin to make 36 pence.
In this example we are finding a group of coins that add to make 44 pence.
Again, 50p is too large.
We can take a 20 pence coin.
This time we can add a second 20 pence coin to make 40 pence.
We cannot take a third 20p coin because 40 pence plus 20 pence equals 60 pence. We cross off the 20 pence coin.
We continue to go through the coins to see if we can add to the 40 pence we have so far.
Adding 10 pence takes us to 50p, which is too large.
Adding 5 pence takes us to 45p, which is too large.
We need 4 more pence to get from 40p to 44p.
We can add two 2 pence coins.
Now try our lesson on British Money Maths: Introducing Pound Sterling Coins where we learn about pound sterling coins.
Here are the numbers 1 to 20:
Writing Numbers to 10: Interactive Questions
Writing Numbers to 100: Interactive Questions
Here are the numbers from one to twenty written in words.
Before teaching reading numbers to 100 in words, it is first important to be familiar with the numbers to twenty.
We will continue by looking at the pattern in reading the numbers from 20 to 100.
To read numbers to 100 in words, first read the multiple of ten given by the tens digit and then read the units digit immediately afterwards. There should always be a hyphen ‘-‘ separating the multiple of ten and the number given by the units digit. The numbers ‘one’ to ‘nine’ repeat, written after each new multiple of ten.
Here is a list of the multiples of ten written in words:
We will first learn how to read numbers in the twenties in words.
20 is the number twenty. All 2-digit whole numbers that start with a ‘2’ digit are in the twenties.
21 starts with a ‘2’ and so it is in the twenties. Therefore we first write ‘twenty’.
21 ends in a ‘1’ in the units column and so we simply write a ‘one’ after the ‘twenty’.
21 is written in words as ‘twenty-one’. We put a hyphen between twenty and one.
22 is written as ‘twenty-two’.
23 is written as ‘twenty-three’
24 is written as ‘twenty-four’.
25 is written as ‘twenty-five’
26 is written as ‘twenty-six’.
27 is written as ‘twenty-seven’
28 is written as ‘twenty-eight’.
29 is written as ‘twenty-nine’
We can see that as long as we know the numbers from 1 to 9, we simply put a ‘twenty’ in front of them to write numbers in the twenties.
30 comes after 29.
30 is read as ‘thirty’ and is the first 2-digit number that starts with a 3.
Here we will read and write the numbers in the thirties. The numbers in the thirties are the 2-digit whole numbers that start with a 3.
31 starts with a ‘3’ and so it is in the thirties. Therefore we first write ‘thirty’.
31 ends in a ‘1’ in the units column and so we simply write a ‘one’ after the ‘thirty’.
31 is written in words as ‘thirty-one’. We put a hyphen between thirty and one.
32 is written as ‘thirty-two’.
33 is written as ‘thirty-three’
34 is written as ‘thirty-four’.
35 is written as ‘thirty-five’
36 is written as ‘thirty-six’.
37 is written as ‘thirty-seven’
38 is written as ‘thirty-eight’.
39 is written as ‘thirty-nine’
Again, we simply repeat the numbers 1 to 9 but with the word ‘thirty’ in front of them. The thirty and the units number are separated by a hyphen.
40 comes after 39.
40 is read as ‘forty’. It is a common mistake to spell forty as fourty, with a ‘u’, like the number four. This is incorrect and forty is spelled without a ‘u’.
All 2-digit whole numbers that start with a ‘4’ are in the forties.
They start with the word ‘forty’, are followed by a hyphen and then the units number.
41 starts with a ‘4’ and so it is in the forties. Therefore we first write ‘forty’.
41 ends in a ‘1’ in the units column and so we simply write a ‘one’ after the ‘forty’.
41 is written in words as ‘forty-one’. We put a hyphen between forty and one.
42 is written as ‘forty-two’.
43 is written as ‘forty-three’
44 is written as ‘forty-four’.
45 is written as ‘forty-five’
46 is written as ‘forty-six’.
47 is written as ‘forty-seven’
48 is written as ‘forty-eight’.
49 is written as ‘forty-nine’
We can see that the rule learnt previously continues.
We simply write the multiple of ten indicated by the first digit and follow this with a hyphen and then the final digit.
After forty, the next multiples of ten are fifty (50), sixty (60), seventy (70), eighty (80) and ninety (90).
The numbers continue to end in ‘one’, ‘two’, ‘three’, ‘four’, ‘five’, ‘six’, ‘seven’, eight’ and ‘nine’.
The last number in this pattern is 99, which is written as ‘ninety-nine’.
After ninety-nine comes one hundred, 100.
Now try our lesson on Ordering Numbers to 100 where we learn how to order the numbers to 100.
