Missing Numbers 1 to 20 Worksheet (Free Printable PDF)

What’s in the PDF

• Page 1 (Level 1, easier): It has six number trains from 1 to 10 with three or four gaps each, and one count-back train from 10 to 1.
• Page 2 (Level 2, harder): It has four trains from 11 to 20, four short gap-filling sequences, and a count-back train from 20 to 11.
• Page 3: an answer key for both levels.

Print one level at a time. If Level 1 feels easy, move straight on to Level 2.

How to teach missing numbers

Filling in missing numbers shows whether children really know the order of numbers or are just reciting a rhyme. Ask your child to point to each carriage and say the numbers aloud, then pause at the gap and decide which number comes next. For teen numbers, keep a number chart close by so they can check how each number is written.

What to watch for

Teen numbers are often reversed, so 13 becomes 31. Say the number, then point out that teen numbers always start with a 1. When counting backwards, children may slip into counting forwards, so start with short count-backs.

Game: Number line gaps

Write 1 to 20 on sticky notes and stick them in a row on the wall. While your child closes their eyes, take one or two away. Can they work out which numbers are missing?

Everyday practice

Look for numbers in order: house numbers on a street, page numbers in a book, a lift panel or the numbers on a clock. Ask what number comes next, or which page comes just before this one.

Questions to ask while they work

• What number comes after 14?
• Which number is missing from 6, 7, ?, 9?
• Can you count back from 20?

Practise next

Try before, after, between, skip counting, counting 1 to 10. Check the answers on the number charts.