Negative or minus numbers are important in KS3 Maths. Integers are whole numbers. They can be positive or negative. Positive numbers are above zero. Negative numbers are below zero and are written with the minus sign in front of the digits. In this quiz you'll learn how addition and subtraction work with negative numbers.

You may wonder why we need negative numbers but we use them all the time. One example is temperatures. Temperatures colder than freezing are negative numbers in the Celsius scale. If you want to know how many degrees more than -5^{o}C is 16^{o}C then you'll need to be able to add and subtract negative numbers. Addition and subtraction can be tricky with negative numbers. One method that might help is to rearrange the problem. For example: 21 - 16 = 5 so 16 - 21 = -5.

It all becomes easier with practise so try this quiz to familiarise yourself. Soon it will all be second nature.

1.

What is -4 - -17?

-21

-13

13

21

When two minus signs occur together, they act as a plus sign

2.

What is -21 + 14 + -9?

-18

-16

18

35

It's useful to use a number line with 0 in the centre

3.

What is -66 + -33 - -22?

-77

-44

44

77

On a number line, count to the left for negative numbers and right for positive numbers

4.

Which of the following numbers is more than -74?

-73

-75

-100

-174

Remember, negative number values get smaller the higher the numbers get

5.

What is 8 + -3?

-11

0

5

11

8 + -3 is the same as 8 - 3

6.

What is 4 - -17?

-21

-13

13

21

You could re-write the calculation as 4 + 17

7.

What is -3 + 8?

-11

0

3

5

Re-arrange the problem to 8 - 3

8.

Which of the following numbers is less than -3?

0

-1

-2

-4

The higher the number, the lower the negative number

9.

What is -4 - 17?

-21

-13

13

21

Subtracting two negative numbers is similar to adding two positive numbers - just remember that the answer will be a negative number

10.

What is 50 - -11 + -3?

39

41

58

61

Two negatives cancel each other out. So, 50 - -11 + -3 is the same as 50 + 11 - 3