Writing Numbers: Why 13 Looks Nothing Like It Sounds in Year 1

Writing Numbers: Why 13 Looks Nothing Like It Sounds in Year 1

This guide helps parents and carers understand why children in Year 1 often write teen numbers backwards, such as writing '31' instead of '13'. It explains that this happens because the spoken word 'thirteen' puts the 'three' first, while the written number puts the 'one' (representing ten) first. We offer simple, playful ways to help your child spot and fix this common mistake without stress.

What it is

In Year 1, children begin to write numbers from 11 to 19. A very common mistake is writing the digits in the wrong order. For example, a child might hear 'thirteen' and write '31' because they hear the 'three' first. This is not a sign of confusion about maths, but rather a clash between how we speak and how we write. In English, teen numbers are spoken with the smaller number first (three-teen), but written with the ten first (13). Understanding this difference is the first step to helping your child correct it gently.

What happens

When children learn to write numbers, they often map sounds directly to symbols, much like they do in phonics. If they hear 'sixteen', their brain may record 'six' then 'one'. When they write it down, they put the '6' first and the '1' second, resulting in '61'. This is a logical error based on listening skills. Teachers in England’s schools often notice this pattern early in Year 1. It is a normal part of learning the place value system, where the position of a digit changes its value. Recognising this pattern helps us support children without making them feel they have failed.

What it means for your child

Seeing your child write '21' for twenty-one can be worrying, but it is rarely a sign of deeper learning difficulties. It usually means your child is still developing their understanding of place value, which is a key concept in the Year 1 maths curriculum. Place value means understanding that the '1' in '15' represents ten, not one. This skill takes time to master. Many children correct this naturally as they gain more experience with numbers. If your child makes this mistake, it is an opportunity to practise, not a cause for alarm. Most children overcome this quickly with gentle guidance.

How you can help at home

Keep practice short and playful. Try saying the number slowly and asking your child to point to the 'ten' first. You might use a visual aid, like two columns labelled 'Tens' and 'Ones'. When you say 'fourteen', ask them to put a '1' in the Tens column and a '4' in the Ones column. Another trick is to emphasise the 'teen' sound: 'One-teen, Two-teen'. This reminds them that the 'one' comes first in writing. Avoid drilling long lists of numbers. Instead, use everyday moments, like reading house numbers or counting steps, to gently check if they are writing the digits in the right order.

Questions parents often ask

Parents often ask if this means their child has dyscalculia, a specific learning difficulty with maths. Usually, it does not. This reversal is a common stage in learning to write teen numbers. If the error persists for a long time despite practice, or if your child struggles with other maths concepts, speak to your child’s teacher. They can tell you if extra support is needed. Another common question is whether to correct every mistake. It is better to focus on a few numbers at a time and praise effort. Remember, every school may have slightly different methods, so always ask your child’s teacher for advice specific to your child’s progress.

Sources

• Department for Education: National Curriculum in England: Mathematics programmes of study
• GOV.UK: Teaching maths in primary schools