Page 133 - New Medley 3 Semester 1

Checking Subtraction by Addition

Example 5: Check the answers of the following:

(a) 9 5 3 8 (b) 7 8 6 4

– 6 2 8 4 – 4 0 3 9

3 2 7 4 3 8 2 5

Solution: We add last two numbers.

If we get their sum as the first number, our answer is
correct, otherwise wrong.

(a) 6 2 8 4 (b) 4 0 3 9
+ 3 2 7 4 + 3 8 2 5

9 5 5 8 7 8 6 4

Different from the first number. Same as the first number.

So, the answer is incorrect. So, the answer is correct.

EXERCISE 3.5

Check the following subtractions by addition. Write your answers in the
blank spaces.

1. 5 6 7 9 2 1 8 0

– 2 1 8 0 + 3 4 9 9 Subtraction is

3 4 9 9 (correct/incorrect)

2. 4 2 8 9 3 1 5 4

– 3 1 5 4 + 1 1 2 5 Subtraction is

1 1 2 5 (correct/incorrect)

3. 8 7 2 4
– 4 6 5 7
Subtraction is
4 0 6 7
(correct/incorrect)

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