Page 18 - 新思维数学学生用书8 样章

1.2 Multiplying and dividing integers

Continued

e Can you make a conjecture about the answer when
you divide an integer by a negative integer?

Test your conjecture.
f Compare your answer with a partner’s answers.
Have you made the same conjectures?

12 Work out these divisions. Tip
a 18 ÷ −6 b −28 ÷ −4 c 30 ÷ −6
d −30 ÷ −10 e 42 ÷ −6 f −24 ÷ −4 Remember,
g 60 ÷ −5 h −25 ÷ −5 division is the

13 Here are three multiplication pyramids. inverse of
a b c multiplication so
–200
you will divide as
6 12 –8 –20 you work down

5 –1 –2 –4 the pyramid.

Copy and complete each pyramid.
14 Work out
a (3 × −4) ÷ −2 b (2 − 20) ÷ −3
c (−3 + 15) ÷ −4 d 24 ÷ (2 × −4)

15 Find the value of x.
a x ÷ −4 = 8 b x ÷ −3 = −15
c 16 ÷ x = −2 d −15 ÷ x = 3
16 Round these numbers to the nearest whole number to estimate

the answer.
a −8.75 ÷ 2.8 b 18.1 ÷ −5.9
c −28.2 ÷ −3.8 d −35.2 ÷ −6.9

17 Round these numbers to the nearest 10 to estimate the answer.
a −48 × −29 b −18.1 × 61.5
c −71.4 ÷ −11.8 d −99.4 ÷ 19

Summary checklist

I can multiply two negative integers.

I can divide any integer by a negative integer.

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