Page 10 - Whole Numbers (Addition and Subtraction)

16. Copy the number sentences for which you cannot find the
answers quickly.

(a) 18 − 9 = . . . (b) 18 − 8 = . . . (c) 18 − 6 = . . .
(d) 18 − 10 = . . . (e) 8 − 4 = . . . (f) 8 − 3 = . . .
(g) 10 − 3 = . . . (h) 13 − 8 = . . . (i) 13 − 7 = . . .
(j) 13 − 9 = . . . (k) 13 − 3 = . . . (l) 13 − 6 = . . .
(m) 13 − 10 = . . . (n) 13 − 4 = . . . (o) 13 − 5 = . . .
(p) 10 − 2 = . . . (q) 12 − 8 = . . . (r) 12 − 7 = . . .
(s) 12 − 9 = . . . (t) 12 − 4 = . . . (u) 12 − 6 = . . .

17. Now complete the sentences that you copied in questions 14,
15 and 16. You may work from the facts that you know, or fill
up to tens, or work in any other way you prefer.

3.4 Addition facts for multiples of 10 and 100

30 + 50 is 3 tens plus 5 tens.
300 + 500 is 3 hundreds plus 5 hundreds.
So, if you know that 3 + 5 = 8,
you can also know that 30 + 50 = 80 and 300 + 500 = 800.

1. How much is each of the following?

If you don’t know the answers immediately, read the text
below and on the next page first. Then try again.
(a) 80 + 70 (b) 700 + 200
(c) 30 + 90 (d) 500 + 400
(e) 80 − 30 (f) 900 − 500
(g) 70 + 90 (h) 140 − 80
(i) 130 − 40 (j) 900 + 500

You can think of movements on a number line when you
count on in tens to do addition:

10 10 10 10 10 10 10 10

60 70 80 90 100 110 120 130 140

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