Maths Library

Counting and Number Words to 20: Year 1 maths

This topic covers one-to-one correspondence, numeral recognition, and writing number words up to 20. Pupils practise counting structured sets of objects, filling in missing numbers in sequences, and matching digits to their written names.

Open in full editor

What this covers

Counting and Number Words to 20 is taught in Year 1 (age 5 to 6, KS1) as a main teaching focus. It sits in the Number strand.

Worked example

Count the stars and write the total as both a numeral and a word: × * × * × * *

  1. Count each star one by one: 1, 2, 3, 4, 5, 6, 7.
  2. Write the digit: 7.
  3. Write the matching word: seven.

Answer: 7 (seven)

Difficulty scale

The sheet generator offers five difficulty settings for this topic.

  1. Counting objects and matching numerals up to 5
  2. Counting structured sets and reading number words up to 10
  3. Finding missing numbers in forward sequences up to 20
  4. Writing number words from numerals between 11 and 20
  5. Counting backwards from 20 and matching mixed representations

Common mistakes

  • Skipping numbers in the tricky teen sequence (e.g., jumping from twelve straight to fourteen)
  • Writing reversed digits such as confusing 12 and 21

Curriculum links

Indicative matches to National Curriculum for England. Check wording and codes against the official document.

  • Count forwards and backwards to and across 100, reading and writing numbers in numerals and words.

Sample sheet and answers

Six questions at the level's usual difficulty. Open the editor to change, add or regenerate any of them.

Counting and Number Words to 20

Year 1 maths

Qs
6
Marks
6
NameDateScore / 6
1.
Fill the gap: 5, 6, , 8
[1]
2.
Fill the gap: 3, 4, , 6
[1]
3.
Fill the gap: 8, 9, , 11
[1]
4.
Fill the gap: 1, 2, , 4
[1]
5.
Fill the gap: 12, 13, , 15
[1]
6.
Fill the gap: 1, 2, , 4
[1]

Answer key

  1. 7The numbers go up by 1; 6 then 7
  2. 5The numbers go up by 1; 4 then 5
  3. 10The numbers go up by 1; 9 then 10
  4. 3The numbers go up by 1; 2 then 3
  5. 14The numbers go up by 1; 13 then 14
  6. 3The numbers go up by 1; 2 then 3