Page 9 - 新思维数学活动用书7 样章

1 Integers

3 Copy and complete this multiplication table.
× 4 7

−2

−6

4 Work out:
a (−5 + 2) × 4 b (−6 + −4) × 3
c (1 − −3) × −7 d (−2 − −5) × −10
5 Work out:

a (−5 + −7) ÷ 4 b (10 − −4) ÷ −2
c (−6 +14) ÷ −4 d (−5 − 13) ÷ 3

Practice

6 Work out the missing numbers.
a 3 × = −24 b 6 × = −18
c −2 × = −26 d −12 × = −60
7 Work out the missing numbers.

a −27 ÷ = −3 b 36 ÷ = −9
c ÷ 6 = −6 d ÷ −4 = −8
8 Estimate the answers to these questions by rounding the numbers.
a −4.1 × 2.8 b −7.1 × −3.2

c −1.1 × −7.9 d −9.1 ÷ 3.2
9 Estimate the answers to these questions by rounding the numbers.
a 423 × −2.9 b 32 × −28
c −6.1 × 219 d −612 ÷ 2.92

10 The product of 2 and −9 is −18.
a Find three more pairs of integers with a product of −18.
b Are there more pairs of integers with a product of −18?
How can you be sure?

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