Year 1 maths · Key Stage 1 · Number – number and place value

Year 1 counting and numbers to 100: a guide for parents

In Year 1 children build a secure feel for numbers up to 100. They count forwards and backwards from any starting number, read and write numbers in numerals, count in 2s, 5s and 10s, and find one more and one less than a given number. They also learn the words for comparing numbers, such as more than, fewer, most and least, which they will use in every part of maths for years to come.

Counting and numbers to 100, explained

Counting sounds simple, but at this age it is made of several separate skills. A child has to know the number names in the right order, match one number name to one object, and understand that the last number said tells you how many there are altogether. Year 1 teachers usually use real objects first, then pictures, then a number line, so that counting means something before it becomes a rhyme. Children count to and across 100 (98, 99, 100, 101, 102), forwards and backwards, and from any starting point rather than only from 0 or 1, so “start at 36 and count on” is a normal classroom request.

Reading and writing numbers comes next. Children read and write numerals up to 100, and the numbers 1 to 20 in words as well as numerals, so they can write “twelve” as well as 12. The teen numbers cause the most trouble because we say the ones before the tens: “thirteen” sounds like three-and-ten but is written 13, with the ten first. Using a hundred square and objects grouped in tens, children also begin to notice that numbers beyond 20 follow a pattern of a tens digit and a ones digit. The full idea of place value is taught in Year 2. In Year 1 the aim is to start seeing the pattern.

Counting in 2s, 5s and 10s is introduced through things children can touch: pairs of shoes, fingers on a hand, ten-pence coins. Saying 2, 4, 6, 8 or 5, 10, 15, 20 and spotting the pattern in the ones digits is groundwork for multiplication later. Counting in 2s from different starting numbers also lets children notice odd and even numbers. Children put things in order too, using first, second, third and so on, and make and continue repeating patterns with objects and shapes.

Finding one more and one less is a Year 1 essential. Children learn that one more is the next number when counting on, and one less is the number just before. They then use the language of comparison: equal to, more than, less than, fewer, most and least. Teachers often model “fewer” for things you can count (fewer apples) and “less” for amounts you measure (less water). Children show numbers with objects, drawings and the number line, and are encouraged to explain a comparison in a full sentence, such as “There are more red cubes than blue cubes because I counted nine and six.”

Words your child will hear

Numeral: The symbol that stands for a number. The numeral for seven is 7.
Digit: One of the ten symbols 0 to 9. The number 47 is written with two digits.
Count on, count back: Say the next numbers in order (count on), or the numbers before in reverse order (count back).
One more, one less: The number straight after, or straight before. One more than 9 is 10.
Fewer: Used when comparing things you can count. Four apples is fewer than seven apples.
Most and least: The biggest and smallest amount in a group of three or more.
Number line: A line with numbers in order, used to count along, compare numbers and see what comes next.

What the National Curriculum says

In Year 1, pupils should be taught to:

Count to and across 100, forwards and backwards, beginning with 0 or 1, or from any given number
Count, read and write numbers to 100 in numerals; count in multiples of 2s, 5s and 10s
Given a number, identify 1 more and 1 less
Identify and represent numbers using objects and pictorial representations including the number line, and use the language of: equal to, more than, less than (fewer), most, least
Read and write numbers from 1 to 20 in numerals and words

Objectives from the National Curriculum in England, © Crown copyright, used under the Open Government Licence v3.0.

A worked example

Count on from 47 to 53. What is one more than 49, and one less than 50?

Put a finger on 47 on a number line or hundred square and count on one at a time, saying each number aloud: 47, 48, 49.
```
47  48  49
```
The next number is the tricky one, because the tens digit changes. 49 is 4 tens and 9 ones. One more makes 5 tens and 0 ones, which is fifty, written 50. On a hundred square the finger moves to the start of the next row.
```
47  48  49  50
```
Keep counting on: 51, 52, 53. Then check by counting back the same way, from 53 to 47. The tens digit changes again as you go from 50 back to 49.
```
47 48 49 50 51 52 53
53 52 51 50 49 48 47
```
Now go the other way. One less than 50 is the number just before it when counting back: 50, 49. So one less than 50 is 49.
Notice the pair: one more than 49 is 50, and one less than 50 is 49. Each answer undoes the other, which is a good thing to say out loud.

47, 48, 49, 50, 51, 52, 53. One more than 49 is 50, and one less than 50 is 49.

Common mistakes and how to help

Reversing digits, so 13 becomes 31 or 16 becomes 61

Children write what they hear. In “sixteen” the six is heard first, so it is written first. The teen numbers are the only ones where we say the ones before the tens.

What helps: Build teen numbers with a full ten frame or ten cubes plus some ones: “one ten and three ones makes thirteen”. Always write the ten first and say what each digit means.

Getting stuck when the tens change, saying “thirty-eight, thirty-nine, thirty-ten”

Children learn the repeating 1 to 9 pattern quickly but have to remember separately that the next tens word follows. The word after thirty-nine is a new word, not a continuation.

What helps: Practise the tens words on their own (ten, twenty, thirty and so on) and use a hundred square to see the end of one row leading to the next. Count out 39 objects, add one more and see that it makes a new group of ten.

Thinking a spread-out group has more than a bunched-up group

Young children often judge amount by how much space things take up, so ten counters in a long line look like more than ten counters in a heap.

What helps: Count both groups and, if needed, match them one to one by pairing each counter with a partner. Ask “How can we be sure?” and let your child find a way to check.

Mixing up one more and one less, or finding counting back harder than counting on

Counting forwards is practised far more than counting backwards, so backwards counting can feel like a different skill. Some children also guess instead of using the number sequence.

What helps: Count back from 20 as a countdown, then from other numbers. Use a number line and say “one less is the number just before”. Ask both questions about the same number so the pair is clear.

How to help at home

Count everything, and change the start. Count stairs, steps to the park, spoons, apples. Sometimes start somewhere else: “Start at 28 and count on to 35.” Try counting back too, such as down from 12 as you tidy up.
Count in 2s, 5s and 10s with real things. Socks and shoes are good for counting in twos, fingers on one hand for fives and both hands for tens, and ten-pence coins for tens. Say the pattern aloud and ask what you notice about the last digit.
Play one more, one less. Roll a dice or turn over a card and ask for one more and one less than the number. Put out two small piles of objects and ask which has more and which has fewer. With three piles, ask which has the most, which has the fewest and how you know.
Spot and write numbers. House numbers, bus numbers, page numbers and the numbers on a clock all count. Your child can write them with chalk outside or a finger in a tray of flour, then say them. Try number words from 1 to 20 on scraps of paper and match them to numerals.

Leads on to

Year 2: Tens, ones and counting in steps

Everything in Year 1 maths

Updated 20 October 2026.