-3
Negative
Numbers
Differences using positive and negative numbers
-11
Chris Clements
-6
<date>
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.
5 - 8 = -3
-5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10
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.
The thermometer is showing that
the temperature is - 6ºC.
10
5
0
-5
-10
ºC
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?
4
-3
-5 -4 -3 -2 -1 0 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?
9
-2
11
6
-8
14
12
-1
13
18
-9
27
24
-7
31
32
-12
44
Negative numbers
What is the difference between the two
temperatures?
10
ºC
10
5
5
0
0
-5
-5
-10
-10
ºC
-6ºC
9ºC
The difference is 15ºC
Negative numbers
What is the difference between the two
temperatures?
10
ºC
10
5
5
0
0
-5
-5
-10
-10
ºC
-9ºC
12ºC
The difference is 21ºC
Negative numbers
What is the difference between the two
temperatures?
Spain
23ºC
Mexico
39ºC
Sweden
-12ºC
35ºC
Iceland
-27ºC
66ºC
Negative numbers
What is the difference between the two
temperatures?
UK
Norway
-3ºC
-8ºC
Canada
-15ºC
Iceland
-27ºC
5ºC
When finding the
difference
between two
negative
temperatures
simply take away
the lowest
temperature from
the highest
temperature.
12ºC
Steps to success
1) Difference between a negative number and a
positive number (add numbers together)
-8ºC
7ºC
Difference is 8 + 7 = 15ºC
2) Difference between two negative numbers; lower
negative number subtract the higher negative
number.
-7ºC -11ºC
Difference is 11 - 7 = 4ºC
Activity
<type here>
Plenary
Which two numbers have a difference of 2?
-1
-0.5
0
0.5
Birmingham
10
5
0
-5
-10
ºC
10
4ºC
ºC
0
-5
-10
1.5
How much colder is it in
Birmingham than Paris?
The following day the
temperature in Paris is 4ºC.
Birmingham is 8ºC colder.
What is the temperature in
Birmingham?
5
-4ºC
1
Paris