Chris Clements

Negative Numbers

Differences using positive and negative numbers

-6

-3

-11

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Learning Objective:

LO: I can find the difference between positive and negative integers.

Negative numbers Negative numbers are the result of a bigger

number being subtracted from a smaller number.

-38 =5 -

109876543210-1-2-3-4-5

Negative numbers Negative numbers are often used when

calculating temperatures.

When using degrees centigrade (ºC) a temperature below freezing is shown by a

negative number.

-10

-5

0

5

10

ºC

The thermometer is showing that the temperature is -

6ºC.The higher the positive number the warmer the

temperature.The lower the negative number the colder the

temperature.REMEMBER: -1 is the highest

whole negative number.

Negative numbers What is the difference between the following

numbers?

-34543210-1-2-3-4-5

The answer is 7

An efficient method for doing this calculation is to add together the positive number to the

negative number;So 4 + 3 = 7 the difference is 7.

Negative numbers Using the method shown can you find the

difference between the following numbers?

-29 -86

-112

-724

-918

-1232

11 14

13 27

31 44

Negative numbers What is the difference between the two

temperatures?

-10

-5

0

5

10ºC

-10

-5

0

5

10ºC

-6ºC 9ºC

The difference is 15ºC

Negative numbers What is the difference between the two

temperatures?

-10

-5

0

5

10ºC

-10

-5

0

5

10ºC

-9ºC 12ºC

The difference is 21ºC

Negative numbers What is the difference between the two

temperatures?

-12ºC23ºC

Spain Sweden

35ºC

-27ºC39ºC

Mexico Iceland

66ºC

Negative numbers What is the difference between the two

temperatures?

-8ºC-3ºC

UK Norway

5ºC

-27ºC-15ºC

Canada Iceland

12ºC

When finding the difference between two

negative temperatures simply take

away the lowest temperature

from the highest

temperature.

1) Difference between a negative number and a positive number (add numbers together)

Steps to success

Difference is 8 + 7 = 15ºC

2) Difference between two negative numbers; lower negative number subtract the higher negative number.

7ºC-8ºC

-11ºC-7ºC Difference is 11 - 7 = 4ºC

Activity

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Plenary

How much colder is it in Birmingham than Paris?

0 1-1 -0.5 0.5

Which two numbers have a difference of 2?

1.5

-10

-5

0

5

10ºC

-10

-5

0

5

10ºC

Birmingham

Paris

The following day the temperature in Paris is 4ºC. Birmingham is 8ºC colder. What is the temperature in Birmingham?

4ºC

-4ºC