Numbers on a number line to 20: what children learn
A number line shows numbers in order with equal spaces between them. Year 1 pupils learn to identify and represent numbers using objects, pictures and the number line, and to use the language of equal to, more than, less than, most and least.
In this game the line runs from 0 to 20 with every number marked by a tick, but only 0, 5, 10, 15 and 20 are labelled. Children have to work out where a number such as 13 goes by counting on from a labelled point. This builds a feel for the size of numbers, which is the foundation for estimating, rounding and mental calculation later on.
This topic covers the Year 1 statutory requirement in the National Curriculum in England (Number – number and place value): pupils should be taught to “identify and represent numbers using objects and pictorial representations including the number line”. Year 1 pupils are usually aged 5–6.
For families following US standards, the closest Common Core standard is 1.NBT.A.1, which is taught in Grade 1. Common Core introduces the number line formally in Grade 2 (2.MD.B.6).
How to play
Move the marker to the right place on the number line, then press Check. You can drag, tap the line or use the arrow keys. Each game has 8 rounds. After you press Check, a green arrow shows the correct position if you were not quite right.
Step by step
- Find the nearest label. Look at the labelled numbers and choose the one closest to the target. For 13, the nearest labels are 10 and 15.
- Count the jumps, not the ticks. From 10, count each gap as one: 11, 12, 13. Three jumps to the right.
- Count back if it is quicker. 14 is one jump left of 15, which is quicker than four jumps right of 10.
- Check with 'more than' and 'less than'. Ask whether the number is more or less than 10. If it is more, the marker should be to the right of 10.
Worked examples
Example 1: Put 7 on the number line.
Working: 7 is between 5 and 10. From 5, count two jumps right: 6, 7.
Answer: Two ticks to the right of 5
Example 2: Put 14 on the number line.
Working: 14 is one less than 15, so it is one tick to the left of 15.
Answer: One tick to the left of 15
Example 3: Put 2 on the number line.
Working: Start at 0 and count two jumps: 1, 2.
Answer: Two ticks to the right of 0
Common mistakes and how to fix them
- Counting the starting tick as 1. Place a finger on the start number and say '0' (or '10'), then count each jump.
- Counting every number from 0 every time. Encourage starting from the nearest labelled number. It is faster and builds number sense.
- Thinking the numbers further left are bigger. Remind children that numbers get bigger as you move right along the line.
Activities to try at home
- Make a number line with chalk on the pavement or masking tape on the floor, and jump to numbers you call out.
- Hang a washing line and peg cards 0, 5, 10, 15 and 20. Ask your child to peg other numbers in the right places.
- Use a tape measure: where is 12 cm?
Ideas for the classroom
- Use a large floor number line and ask pupils to stand at numbers, then compare: who is standing at the larger number?
- Give pairs blank lines from 0 to 20 marked only at 0 and 20 and ask them to estimate where 10 and 5 would go.
- Link to bead strings in groups of five to show the same structure.
Printable worksheet
The printable worksheet uses the same question generator as the game, so it practises exactly the same skills. It comes with a separate answer sheet on the second page. Print it, or save it as a PDF from your browser's print menu.
Frequently asked questions
Why are only some numbers labelled?
If every number were labelled, the game would only test reading. Labelling every fifth number makes children count on or back, which is the skill that matters.
Can my child play without a mouse?
Yes. Use the slider with the arrow keys, tap the line on a touch screen, or drag the marker.
What comes after this?
In Year 2 children use number lines to 100. In Year 3 they place fractions on a number line, and in Year 4 decimals.