Numbers on a number line to 20: what children learn
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 labeled. Children have to work out where a number such as 13 goes by counting on from a labeled point. This builds a feel for the size of numbers, which is the foundation for estimating, rounding and mental calculation later on.
Supports part of Common Core 2.MD.B.6. This focused game does not cover the entire standard.
Common Core connection: 2.MD.B.6. This is focused practice for part of the standard.
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 labeled 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 labeled 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 sidewalk 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 students 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.
Free printable game and worksheet
The free printable starts with a game sheet, such as a color-by-answer picture, an answer maze or a secret-code joke, followed by a worksheet. Both use the same checked questions as the online game, and the answers are on the last page. Print it, or save it as a PDF from your browser’s print menu.
Open the free printable game and worksheet
Frequently asked questions
Why are only some numbers labeled?
If every number were labeled, the game would only test reading. Labeling 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.
How should I choose this game for my learner?
Supports part of Common Core 2.MD.B.6. This focused game does not cover the entire standard.