Unofficial Christ's Hospital Forum

Foureyes wrote: ↑Sat Aug 21, 2021 5:22 pm I am researching the development of handheld/desktop calculators and would be grateful for any help on an unusual mechanical device I remember being used by some boys at Housie during my time there - 1948-1955. I have searched Google but cannot find it, but a keyword would help.
It fitted into the hand and the frame was made of metal and was quite thin. There were a series of vertical sliders, each with holes numbered 0-9. It was operated by a stylus which was inserted into the appropriate hole and then moved (I think) downwards. If the resulting figure exceeded 9 the stylus was then used to track sideways to the next column. As you can see, my memory is a bit hazy, but, hey, it was a long time ago!
As I recall, it was quite expensive so only a few people had one.
I emphasis that it was entirely mechanical (handraulic, as they say), there was no question of electrical operation.
Any help gratefully received,
David

Foureyes wrote: ↑Sat Aug 21, 2021 5:22 pm I am researching the development of handheld/desktop calculators and would be grateful for any help on an unusual mechanical device I remember being used by some boys at Housie during my time there - 1948-1955. I have searched Google but cannot find it, but a keyword would help.
It fitted into the hand and the frame was made of metal and was quite thin. There were a series of vertical sliders, each with holes numbered 0-9. It was operated by a stylus which was inserted into the appropriate hole and then moved (I think) downwards. If the resulting figure exceeded 9 the stylus was then used to track sideways to the next column. As you can see, my memory is a bit hazy, but, hey, it was a long time ago!
As I recall, it was quite expensive so only a few people had one.
I emphasis that it was entirely mechanical (handraulic, as they say), there was no question of electrical operation.
Any help gratefully received,
David

Foureyes wrote: ↑Sun Aug 22, 2021 5:47 am I well remember the Chinese shopkeepers in places such as Change Alley in Singapore who were really, really fast. When they went clickety-click (etc) on their abacus and then said, "that's a special price for you, Tuan, twenty-five dollars thirty" it was impossible for the bewildered Brit to argue because he or she had absolutely no idea how the calculation had been made.
David

Katharine wrote: ↑Sat Aug 21, 2021 9:53 pm It sounds something like a development of an abacus, but I can’t say any more than that.

If you have ever seen someone using an abacus skilfully it is surprising how quickly they can do it, and, of course, get the right answer. Even more surprising is seeing someone make the same movements without a physical abacus and still get the right answer!

sejintenej wrote: ↑Sun Aug 22, 2021 8:19 pm

Katharine wrote: ↑Sat Aug 21, 2021 9:53 pm It sounds something like a development of an abacus, but I can’t say any more than that.

If you have ever seen someone using an abacus skilfully it is surprising how quickly they can do it, and, of course, get the right answer. Even more surprising is seeing someone make the same movements without a physical abacus and still get the right answer!

I suspect that you saw Mrs Macarian's pupils on Blue Peter. The primary school pupils were using the implements but those in their first year at secondary school just used fingers. Her lessons were discontinued because the school could not afford the one lesson per week time. They were using Sorobans which are Japanese equivalent of the Chinese abacus but different in that the soroban works in units of five instead of ? ten. She taught me and my soroban is beside my desk alongside my ancient slide rule.

Katharine wrote: ↑Mon Aug 23, 2021 5:51 pm I was a long time advocate of a slide rule!

jhopgood wrote: ↑Mon Aug 23, 2021 9:52 pm

Katharine wrote: ↑Mon Aug 23, 2021 5:51 pm I was a long time advocate of a slide rule!

Still have mine.
For a long time I opposed the use of calculators in schools as GIGO. If you have no idea of the answer, how do you know if the calculator is correct?
I taught my children long division as their primary school teacher in Amsterdam advocated the calculator.
Futile conversation. I was not impressed.