Page 44 - Whole Numbers (Addition and Subtraction)

You can form two subtraction facts from any addition fact.
For example, if you know that 1 800 + 700 = 2 500, you also know
that 2 500 − 1 800 = 700 and 2 500 − 700 = 1 800.

8. Form two subtraction facts from each of the addition facts you
formed in question 7.

9. Complete each addition fact and form two subtraction facts
from it.
(a) 800 + 700 (b) 1 800 + 700
(c) 2 800 + 500 (d) 4 600 + 900

(e) 5 970 + 50 (f) 5 700 + 500

You can easily form new subtraction facts from a subtraction fact
you already know.
For example if you know that 1 000 − 300 = 700, it is easy to
form the following facts and others too:
2 000 − 300 = 1 700 5 000 − 300 = 4 700
1 000 − 300 = 700 1 000 − 300 = 700

+ 1 000 + 1 000 + 4 000 + 4 000

2 000 − 300 = 1 700 5 000 − 300 = 4 700

0 100 200 300 400 500 600 700 800 900 1 000

1 000 1 100 1 200 1 300 1 400 1 500 1 600 1 700 1 800 1 900 2 000

4 000 4 100 4 200 4 300 4 400 4 500 4 600 4 700 4 800 4 900 5 000

4 200 4 300 4 400 4 500 4 600 4 700 4 800 4 900 5 000 5 100 5 200

100 200 300 400 500 600 700 800 900 1 000 1 100

10. How much is each of the following?

(a) 5 200 − 300 (b) 1 100 − 300
(c) 1 100 − 400 (d) 1 100 − 500

43