Page 6 - 新思维数学活动用书7 样章

1 Integers

1.1 Adding and subtracting integers

Worked example 1.1 Key words

Work out: integers
a −5 + 9 b 2 − −5 inverse
negative integers
Answer number line
a Draw a number line if you need to.
Start at −5. Move 9 places to the right. positive integers

You finish at 4. −5 + 9 = 4
b To subtract −5, add the inverse, 5.
2 − −5 = 2 + 5 = 7

Exercise 1.1

Focus

1 Add these positive and negative integers.
a −3 + −4 b 6 + −5 c −7 + 2 d −5 + 10
2 Subtract these positive and negative integers.

a 4 − 6 b −6 − 3 c 1 − −8 d −5 − −6
3 Copy and complete this addition table.

+ 4 −5

2

−6

4 Work out:
a 20 + −5 b −10 + −15 c −2 + −13 d −3 + 20

5