Maths Follow Up

Subtraction in Parts

LI:We are learning to subtract by splitting numbers into parts instead of counting down.

Exercise 1

Meera looked at 55 – 18 and said this is the same as 55 – 10 - 8 even though she did not work out the answer. How did she know?

For each of the following problems circle true or false.

1) 41 – 15 is the same as 41 – 10 – 5                   T F

2) 68 – 29 is the same as 68 – 20 – 8                   T F

3) 73 – 15 is the same as 73 – 5 – 20                   T F

4) 85 – 19 is the same as 85 – 11 – 8                    T F

5) 43 – 29 is the same as 43 – 20 – 3                     T F

6) 44 – 15 is the same as 44 – 5 – 10                     T F

7) 58 – 19 is the same as 58 -12 – 7                       T F

8) 36 – 17 is the same as 36 – 7 – 10                     T F

Exercise 2

For each of the following fill in the box or circle.

1) 55 – 18 = 55 – 10 - 8 = 36

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(2) 65 – 19 = 65 – 9 - 10 = 46

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(3) 46 – 28 = 46 – 8 - 20 = 18

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4) 41 – 12 = 41 - 6 - …6 = 29

(5) 94 – 25 = 94… - 5 - 20 = 69

(6) 62 – 28 = 62 - 20 - …8 = 34

7) 36 – 17 = 36… - 10 - 7 = 19

(8) 52 – 25 = 52 - 20 - 5 = 27

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(9) 63 – 36 = 63 - 6 - 30 = 27

10) 73 – 15 = 73 – 10 - …5 = 58

(11) 423 - 17 = 423 - …10 - 7 = 406

(12) 306 – 27 = 306 - 20 - 7 = 279

567- 47 = 567 - 7 - 40 = 520

759 -39 = 759 - 30 - 9 = 720


Today for maths my group had to solve these equations by subtracting by splitting numbers into parts instead of counting down.