What is a number line?
So, what is a number line?
A number ladder is the vertical version of a number line.
How are number lines used?
Number lines are often used in Key Stage 1 for demonstrating addition and subtraction. Children may be given a number line marked 0 - 10 or 0 - 20:
A child might be given the following question:
7 + 2 =
They will be shown how to put their finger on the 7 and then count on 2 until they get to 9. This makes the idea of a number increasing very visual for them.
For this question:
9 - 4 =
children will be asked to put their finger on the 9 and then jump back 4 until they get to 5.
In Year 3 and 4 a number line can be used to work out times table questions, for example: if a child is asked what 4 x 3 is, they could jump along a number line in 3s four times to reach the number 12:
Number lines can also be used for division. If a child has to work out 18 ÷ 3, they could put a mark on the 18 and then jump up to the 18 in 3s. They would then realise they had moved 6 jumps and therefore the answer is 6:
In Year 4, children start to use a number line to understand the concept of negative numbers:
From Years 4 to 6, children would need to place decimal numbers and fractions onto a number line. For example, they may be asked to write what fraction this arrow is pointing at:
They may also be asked to write what decimal this arrow is pointing at:
Some teachers may also use an empty number line to demonstrate dividing larger numbers: