Miss Britton

Ones v. Units: A Place Value Debate

~ 1st June 2020 ~

When teaching the concept of place value, what terminology do you use?

Hundreds, tens and units? Or hundreds, tens and ones?

What is the difference? Is there a “right” way? Why does it matter?

It matters, in my opinion, because differences in terminology can cause confusion for the learners, leading to misunderstandings and misconceptions. We should be careful not to build any additional and unnecessary barriers to children’s learning.

barrier to learning

So what vocabulary should we be using?

In this journal entry, I share my own experiences, explore some of the arguments for and against both ‘Ones’ and ‘Units’ whilst offering the opinions of fellow teachers and education professionals, before drawing my own conclusion.

No More Units?

Throughout my own education, I had always been taught to use H, T, U (hundreds, tens and units) so naturally, when I became a teacher, this was the terminology I used. However, when the 2014 curriculum was released, “units” were now referred to as “ones” in the official documentation so I wondered whether we’d be asked to change the way we taught.

We weren’t.

There was no set guidance on the terminology we should use. While observing others, I began to notice that different terminology was being used by different teachers across the school. In my work as a private tutor, it also came to my attention that the language used varied from school to school and classroom to classroom.

No wonder some children were confused…


I wanted to find out what vocabulary was most commonly being taught as well as the reasons for and against “ones” and “units”.

Here is what I found:

In Favour of “Ones”

  • The name “ones” is more in line with the names of the other place value columns e.g. hundreds, tens, tenths etc.
  • “Ones” is the terminology used in the national curriculum.
  • This vocabulary is compatible with new schemes of work – e.g. White Rose Maths
  • The term “units” can be confusing as it is also used when discussing units of measurement e.g. cm, kg, ml.

In Favour of “Units”

  • Tradition. This is the language that many teachers are familiar with – if it ain’t broke, don’t fix it!
  • Using “units” means old textbooks can continue to be used, meaning no unnecessary waste.
  • When using “units”, the column can be clearly labelled with “U” whereas when “ones” is the preferred term, “O” can easily be confused with 0 (zero).

What do other people say?

Having identified the pros and cons of both “units” and “ones”, I was keen to find out the opinions of fellow teachers so I created an #EduTwitter poll.

With a whopping 84.3% of the votes, “ones” is clearly the preferred term amongst teachers on Twitter.

Here are some of the responses to the poll:

“I’d say there’s been a swing towards ‘ones’ over the last few years. It has much more meaning to children as thinking of ‘five’ as 5 ones makes more sense than 5 units!”

James owner of numberstacks.co.uk.

“Units can be units of one, units of ten, units of a hundred etc as well as cm, mm, packets, boxes. Easier to teach children ’10 ones equal 1 ten'”

Mark Williams

“We use ones mostly, but intersperse units as well so that children are exposed to both.”


“I try very hard to remember to say ones but sometimes units slip out! I have explained to class why that might happen – I explained speech marks and inverted commas for the same reason”

Nei Peel

“The dienes are called flats, rods and units aren’t they. But they can represent anything. The ‘units’ can be e.g. ones or tenths or hundredths. I remember unit cubes at school so I suppose that’s where the conflation with ones came in.”

Mrs Oakman

“Ones but units still keeps slipping out! It was so long we were using units for!”


To share your views and get involved in the discussion, click the button below.


Following this research, I have decided that I will be using the term “ones” rather than “units” to teach place value from now on.

I have come to this conclusion due to the fact that “units” is often confused with “units of measure” and because “ones” is more in keeping with the rest of the place value vocabulary e.g. tens, hundreds, thousands.

Although I think “ones” is the better term for place value, I do believe that children should be familiar with the word “unit”, even if only to help them use Dienes/Base Ten equipment, where a “unit cube” can represent ones, tenths, cms etc.

It is also worth children knowing about units so that they are not confused when moving to high school or being taught by a supply teacher who may use different terminology.

Whilst I will be using “ones” within my own teaching, I have made my resources compatible with both “ones” and “units” to cater for all teachers and students.

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About the Author

Julianne Britton

Julianne Britton is an experienced teacher and author. Having taught across KS1 and KS2 and after just 3 years, she was promoted into leadership and given the responsibility of 'Science and Computing Coordinator'.

Specialising in 11+ entrance exams and SATs preparation, she has also worked as a private tutor, successfully supporting the education of 50+ students and, in addition to writing for CGP Books and Teach Primary magazine, Julianne also publishes educational resources for teachers on TES.

Julianne is also a member of MENSA.

Get in touch via sales@missbritton.co.uk, Twitter or LinkedIn.

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