# Subtracting positive numbers

## Lesson details

### Key learning points

1. In this lesson, we will explore the relationship between subtracting positive numbers and adding additive inverses.

### Licence

This content is made available by Oak National Academy Limited and its partners and licensed under Oak’s terms & conditions (Collection 1), except where otherwise stated.

## Video

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## Worksheet

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## Starter quiz

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### 6 Questions

Q1.
Which word best fills in the gap in this sentence: We can think of addition as _____________ a point on the number line.
fixing
turning
Q2.
Two numbers are additive inverses if their sum is _____.
equal
negative
opposite
subtraction
Q3.
Which sentence best describes the calculation: 3 +(-4) = -1?
A point starts at (-1), is translated 4 spaces to the left and finishes at -3.
A point starts at (-4), is translated 3 spaces to the left and finishes at -1.
Correct answer: A point starts at 3, is translated 4 spaces to the left and finishes at -1.
Q4.
What is the additive inverse of -4.2?
-4.2
0
42
Q5.
Joanna thinks the following calculation pair are additive inverses: 10 + (-50) + (-18) and (-10) + 50 + 18. Is she correct?
No, Joanna is incorrect.
Correct answer: Yes, Joanna is correct.
Q6.
Write the sum that the number line is modelling.
82 - (-8) = 90
82 + (-8) = 90
90 - 8 = 82
Correct answer: 90 + (-8) = 82

## Exit quiz

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### 7 Questions

Q1.
Fill in the gap: Two numbers are additive inverses if their sum is _____.
equal
negative
opposite
subtraction
Q2.
Which words (in order) best complete this sentence: __________________________ can be viewed as the addition of the ____________________________.
Sum, subtraction
Q3.
Which numbers best complete this number sentence in order: 9 - ___ = 9 + ___ = 4
(-13), 13
(-5), 5
13, (-13)
Q4.
Select the calculation that could be represented by this diagram.
-12 - 10 = -2
-2 - 12 = 10
Correct answer: 10- 12 = -2
Q5.
Calculate 2-5
-7
3
7
Q6.
Calculate (-2)-5
-3
3
7
Q7.
Calculate (-2) + (-5)
-3