Page 38 - Whole Numbers (Addition and Subtraction)
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4. Find the missing number in each case.
(a) 2 137 + . . . = 2 200 (b) 3 437 + . . . = 3 500
(c) 2 364 + . . . = 2 400 (d) 4 917 + . . . = 5 000
(e) 4 286 + . . . = 4 300 (f) 5 324 + . . . = 5 400
5. Calculate 5 968 − 3 324 by adding on.
3 324 + . . . → . . . + . . . → . . . etc.
6. (a) How much is each of the following?
5 000 − 3 000 900 − 300 60 − 20 8 − 4
(b) Calculate (5 000 − 3 000) + (900 − 300) + (60 − 20) + (8 − 4).
7. If your answers for questions 5 and 6(b) are not the same, you
have made a mistake. Correct it if this is the case.
To calculate 6 878 − 4 465 you can break both numbers down into
place value parts, work with the parts of the same kind, and then
build the answer up.
Break down:
6 878 = 6 000 + 800 + 70 + 8
4 465 = 4 000 + 400 + 60 + 5
Work with the parts:
6 000 − 4 000 = 2 000
800 − 400 = 400
70 − 60 = 10
8 − 5 = 3
Build up the answer:
6 878 − 4 465 = 2 000 + 400 + 10 + 3 = 2 413
The above actions can also be described by using brackets:
6 878 − 4 465 = (6 000 + 800 + 70 + 8) − (4 000 + 400 + 60 + 5)
= (6 000 − 4 000) + (800 − 400) + (70 − 60) + (8 − 5)
= 2 000 + 400 + 10 + 3
= 2 413
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