What are negative numbers?

What are negative numbers?
We explain what negative numbers are and how children can be taught the concept using a number line, as well as looking at the types of questions that children might be asked involving negative numbers.

What are negative numbers?

A negative number is a number smaller than zero. It can be demonstrated to children by using either a horizontal number line or a vertical number line (number ladder):

Working with negative numbers in primary school

Negative numbers are introduced in Year 4 where children are asked to place a variety of negative and positive numbers on a number line in order. Children may also be asked to work out problems involving negative and positive temperatures.

Children will usually use number lines like those above to help them with these problems. An example of one of these problems is:

The temperature on Monday morning is -5˚C. The temperature on Friday morning is 1˚C. How much warmer is it on Friday morning than on Monday morning?
(Answer: 6˚C)

In Year 6, children will need to calculate with negative numbers mentally, so they will be asked to find the difference between a negative number and a positive number, or two negative numbers.  They will usually start by using a number line to work out these calculations, but later will move onto working them out in their heads.

Example questions might include:

What is 6 minus 12? (-6)

What is -7 plus 18? (11)

The temperature is 5˚C and then drops 9˚. What is the temperature now? (-4˚C)

By Year 6, children are asked to read positive and negative temperatures on a line graph such as the following: