Tag Archives: Calculator

165. What’s that button do again?

Back in post 73: ‘Calculators: The New Hope’ I discussed using a simple worksheet to identify issues with calculators and to get students to write their own help guide. That worksheet is now available in pdf format: How to use a Calculator. There is also a new link on the original post.


Note: Even if your school doesn’t use that particular make/model of calculator it’s still a good discussion resource or starting point for your own worksheet.

131. App of the Day: MyScript calculator

A short post today. This week J introduced me to the ‘MyScript Calculator’ app.


It’s a rather nifty app that converts freehand writing into mathematical calculations and solves them. It is available for most formats of smartphone and you can visit their website here.

These examples from the website show what it is capable of doing – I’m sure there is a lesson here somewhere.


108. Sumlock

This has got to be my geekiest purchase from an antiques and collectors fayre:


It is a working decimal comptometer from the 1960s. To be specific it is a Sumlock model 912/s sterling currency comptometer. It measures 330mm by 315mm by 135mm and was made by the Bell Punch Company. The maximum total it can display is £1,500/17s/11d. This is pre-decimal British currency.


I’m fascinated by old maths and science tools and books. I have an old maths instruction pamphlet from the 19th century with a chapter entitled ‘Mathematics for idiots and women’! So this comptometer is just my kind of thing. When my mother-in-law saw it, she told me about their use in offices. She worked with a comptometer operator in the pay office. Comptometer operators had to be specially trained and earned more than your average ‘office girl’.

I’ve been doing some research and found a rather marvellous website: The Vintage Calculator web museum.

The Sumlock Mechanical Calculator page explains all about this machine. It includes pictures of the internal gear mechanism.

There is also a section on ‘Operating a comptometer’. The processes and algorithms that an operator had to learn were quite complicated and they still had to use mental arithmetic – nothing like modern calculators.

I’m sure there is an arithmetic lesson here somewhere…

73. Calculators: The New Hope

Shameless Stars Wars reference!

To explain: My Foundation GCSE class are finally realising that if they work, they might just get that elusive Grade D or even C. This is my ‘Hope’. They have been doing well with the D to C essential skills sheets by @MathedUp and are developing a positive attitude.

The ‘New’ thing is they have shown an interest in knowing how their* calculators work, for the calculator paper.

‘You mean that little button will work out powers for me?’!

* When I say their calculator I of course mean mine – they haven’t got as far as bringing in theirs from home!

I used Google images to find a clear picture of the calculators we use in school. I put it in the middle of a page and surrounded it with common calculator topics/problems:


We discussed how to use the calculator with each problem. The best students labelled the buttons, gave instructions on how to use them and even asked me for simple examples for each case. This is an example of a pupil’s sheet:


I was very impressed by their attention to detail. I gave them no instruction on what to write and they produced good revision resources. This would be a good activity for KS3 as well as D/C border students.


Update: 21st November 2013

My worksheet is available here: How to use a Calculator