Page 31 - 新思维数学学生用书7 样章

2 Expressions, formulae

and equations

Getting started

1 Work out:
a 14 + 5 b 21 − 7 c −6 + 4 d 12 − 15

e 4 × 8 f 45 ÷ 9 g −8 × 2 h 36 ÷ −3
2 Work out the following. Remember to use the correct order of operations.
a 7 + 2 × 3 b (8 + 4) × 7 c 9 + 12 ÷ 3 d (8 − 5) ÷ 3
_
e 15 × 7 f 18 6 g −6 × 2 − 8 h _ 5 + 10
5 3 2
3 Fill in the missing numbers in each of these calculations.

Choose from the numbers in the circle on the right. 11 2
a + 6 = 8 b × 4 = 24 c ÷ 2 = 5 3 –5
d − 2 = 9 e 4 × = −20 f −18 ÷ = −6 10 6
4 Work out the answers to these problems. Show all your working.
a Karin buys three pizzas that cost $2.75 each and a drink that costs $0.89.

What is the total cost?
b Izzy and Sam go for a meal in a restaurant. They order food that costs $8.70,

$3.45 and $12.25. They share the cost of the meal between them. How much do
they each pay?
5 In this number pyramid, you
find the number in each block
by adding the numbers in the 8 + 12 = 20, so 20

two blocks below it. Complete goes here 8 12 4 7
the number pyramid.

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