Reading the number line
You learn to read which number goes with an arrow on a number line.
How to work it out
- Look how many steps there are between two numbers on the line.
- Divide the difference by that number: that is how much one step is worth.
- Count the steps from the number before the arrow.
A worked example
Which number goes with the arrow?
- There are 10 steps between 30 and 40.
- One step is 10 ÷ 10 = 1.
- The arrow is 4 steps after 30: 30 + 4 = 34.
More examples
Which number goes with the arrow?
- There are 2 steps between 60 and 70.
- One step is 10 ÷ 2 = 5.
- The arrow is 1 step after 60: 60 + 5 = 65.
Which number goes with the arrow?
- There are 5 steps between 500 and 600.
- One step is 100 ÷ 5 = 20.
- The arrow is 3 steps after 500: 500 + 60 = 560.
Watch out
You think every step is worth 1: on a line with steps of 20 you read 503 instead of 560.
Always work out what one step is worth before you start counting.
You count from the start of the line instead of from the number just before the arrow.
Find the big numbered mark just before the arrow, and count on from there.
Tips
- Count the gaps between the marks, not the marks themselves.
- Say out loud what one step is worth before you start counting.
Why it works
Not every mark on a number line is worth 1. Sometimes a step is 5, 20 or 1000. If you work out first how much one step is worth, you can read any number line, however big the numbers are.