How_To_Be_Good_At_Math

80 CALCULATING •^ ADDING WITH A NUMBER LINE

Adding with a

number line

Doing calculations in your head can be tricky. We can use

a number line to help us with calculations, including addition.

It is most useful for calculations with numbers up to 20.

The answer is 70

We need to add 3 to 4,

so next jump 3 places to

the right. This takes us to 7.

So, 4 + 3 = 7

This calculation starts with

the number 4, so first find

4 on the number line.

First, we draw a line

and mark it with

numbers from 0 to 10.

Let’s use a number line to

find out the answer when

we add 4 and 3.

Making leaps

Some calculations involve

using larger numbers.

We can still use a number

line, we just have to make

bigger jumps to find

the answer.

Let's use a number

line with larger

numbers to find 20 + 50.

Starting with the bigger

number, we just have to

jump 2 lots of 10 along our

number line. The answer is 70.

4 + 3 = 7

4 + 3 =?

0 4321 5 6 7 8 9 10

0 4321 5 6 7 8 9 10

0 4321 5 6 7 8 9 10

0 40302010 50 60 70 80 90 100

Jump 2 lots of 10

1 1 1

So, 20 + 50 = 70

The line doesn't have

to be neat – it's just

to help you count

Start counting at 4

Stop counting

at 7

You can use number lines to

work out both addition and

subtraction calculations.

+ + = 3

10 + 10 = 20

080_081_Adding_with_a_number_line_Adding_with_a_number_grid.indd 80 29/02/2016 18:02