Page 35 - Whole Numbers (Addition and Subtraction)

Whole nUmbers:

Addition And sUbtrAction

9.1 Another way to add

One way to calculate 3 785 + 4 667 is to break the 4 667 down into
its place value parts and add them one by one to 3 785:
4 667 = 4 000 + 600 + 60 + 7
3 785 + 4 000 = 7 785
7 785 + 600 = 8 385
8 385 + 60 = 8 445
8 445 + 7 = 8 452

The smaller parts can be added first if you prefer to do so:
3 785 + 7 = 3 792
3 792 + 60 = 3 852
3 852 + 600 = 4 452
4 452 + 4 000 = 8 452

1. Calculate.
(a) 1 212 + 8 688 (b) 5 421 + 3 399

(c) 5 583 + 3 489 (d) 7 354 + 1 687
(e) 4 675 + 4 588 (f) 4 789 − 2 334
2. (a) Calculate 2 000 + 600 + 40 + 5 + 3 000 + 200 + 30 + 3 in the
order in which the numbers are given.

(b) Will you get the same answer if you rearrange the numbers
as done in the line below, and do the calculations in the
order in which the numbers are now written?
2 000 + 3 000 + 600 + 200 + 40 + 30 + 5 + 3
(c) Do the calculations to check your answer.

3. Rearrange the numbers in
5 000 + 800 + 60 + 4 + 3 000 + 500 + 70 + 3
so that the thousands parts are together, also the hundreds
parts, the tens parts and the units parts.

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