Page 33 - SK Year 5 Mathematics DLP

4 750 530 – 128 910 – 58 072 – 9 980 = Round off all numbers to the
nearest ten thousands first.
Step 1 Estimate the answer. Then, subtract.

750 530 750 000 58 072 60 000

128 910 130 000 9 980 10 000

5 12
7 5 0 0 0 0 6 2 0 0 0 0 5 60 0 0 0
– 1 3 0 0 0 0 – 6 0 0 0 0 – 1 0 0 0 0
6 2 0 0 0 0 5 6 0 0 0 0 5 50 0 0 0

Step 2 Calculate the actual answer.

9 11 11 12 14
4 1015 5 1 11 5 1 10 5 2 414
7 5 0 5 3 0 6 2 1 6 2 0 5 6 3 5 4 8
– 1 2 8 9 1 0 – 5 8 0 7 2 – 9 9 8 0
6 2 1 6 2 0 5 6 3 5 4 8 5 5 3 5 6 8

553 568 is nearer to 550 000. The answer is reasonable.

750 530 – 128 910 – 58 072 – 9 980 = 553 568

5 How many need to be subtracted from 509 108 to make 417 293?

509 108 – = 417 293
Relate a simple example to solve.

Simple example. 10

4 – 3 = 1 4 10 8 010
4 – 1 = 3 5 0 9 1 0 8
– 4 1 7 2 9 3
9 1 8 1 5

509 108 − 91 815 = 417 293

91 815 need to be subtracted from 509 108 to make 417 293.

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1.6.2