Subtract multiples of ten from 2-digit numbers | Maths

Starter quiz

19 + 40 = ? How many tens is being added to 19 in this equation? ______ tens

'4' ✓
Look at the image. Which equation does it represent?

36 + 30 =

26 + 40 = ✓

16 + 50 =
Match the known facts that will help to add multiples of 10

2 + 4 = 6

⇔

2 tens + 4 tens = 6 tens ✓

5 + 3 = 8

⇔

50 + 30 = 80 ✓

4 + 5 = 9

⇔

40 + 50 = 90 ✓
What could we do to help solve this equation? 32 + 50 =

Add 3 tens and 5 tens ✓

Add 3 tens and 2 tens

Add 2 tens and 5 tens
Which of these equations will have the same sum as 54 + 40 = ?

40 + 54 = ✓

44 + 50 = ✓

45 + 40 =
33 + 40 = ______

'73' ✓

Exit quiz

Look at the number line. What equation is it showing?

73 − 20 =

73 − 30 =

73 − 40 = ✓
86 − 50 = ? How many tens are being subtracted from 86 in this equation? ______ tens

'5' ✓
Which of the images represent this equation? 82 − 40 =
Match the known facts that will help to subtract multiples of 10

5 − 2 = 3

⇔

5 tens − 2 tens = 3 tens ✓

8 − 6 = 2

⇔

80 − 60 = 20 ✓

9 − 4 = 5

⇔

90 − 40 = 50 ✓
What could we do to help solve this equation? 75 − 30 =

Subtract 3 tens from 7 tens ✓

Subtract 3 tens from 5 tens

Subtract 5 tens from 7 tens
86 − 60 = ______

'26' ✓

Worksheet

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Lesson Details

Key learning points

When subtracting multiples of ten from a two-digit number, the tens digit changes but the ones digit stays the same.
We can use number facts to help us subtract multiples of ten from a two-digit number.

Common misconception

Children may automatically count back in tens to subtract a multiple of ten.

Discuss efficiency and compare different methods. Use practical equipment to draw attention to the relationship between adding multiples of ten in two-digit numbers and the known facts they already possess.

Keywords

Multiples of ten - The numbers that are said when we count on in tens from zero. Multiples of ten always have a ones digit of zero.
Recombine - To add the parts of a number gained through partitioning the whole to reach the whole again.