← Number and place value

Year 1 · Maths

1 less

Knowing 1 less than any number to 20 without counting from 1, down to 1 less than 1, which is 0.

Print a new sheetOpens a PDF. Every sheet has different questions.

New sheets start on target. You can also print an easier one or a harder one.

What your child will see

The whole sheet as it prints. Every new sheet has different numbers.

Write the number that is 1 less.

11 less than10is21 less than1is31 less than16is41 less than20is51 less than19is61 less than17is01234567891011121314151617181920

Two minutes at home

Ask
What is 1 less than 14? And 1 less than 1?
Play
Sing "Five little ducks" with numbers up to 20: start with 13 ducks, one swims away, how many now?

Common mistakes and how to help

  • Wrote 1 more instead of 1 less, as in 15 for 1 less than 14.

    Try this: Line up some spoons and take one away. "1 less" means one fewer: are there more spoons now, or fewer?

  • Wrote the same number: they may not have taken the one away yet.

    Try this: Put 6 grapes on a plate and eat one. Count them again: are there still 6?

  • The digits are the wrong way round, as in 31 for 13. "Thirteen" says the 3 first, but we write the 1 first.

    Try this: Say "thirteen is ten and three" and write the 1 for the ten first, then the 3.

  • Stuck going back past a ten, as in 29 or 10 for 1 less than 20, or 0 for 1 less than 10: the number before a ten may not be secure yet.

    Try this: Make 20 with two full egg boxes (or ten frames). Take one away: one box is full and the other has 9, so 19.

  • The answer is a long way off: the order of the numbers to 20 may not be secure yet.

    Try this: Point to a number on a number track and ask what comes just before it. Check by counting back one.

Curriculum links

  • Given a number, identify 1 more and 1 less.

    National curriculum in England: mathematics programmes of study · Year 1 Mathematics: Number and place value

Department for Education. Contains public sector information licensed under the Open Government Licence v3.0. Department for Education. Contains public sector information licensed under the Open Government Licence v3.0.