OT Can people not do mental arithmetic or use a calculator any more?

[hgt]

Can't see that with most life activities and I was always brilliant at maths.

But that isn't a common life activity.

[SteveW]

Our youngest is 14, they were definitely still teaching times tables when he was in primary school.

[SteveW]

While I remembered (and still do) pi to 11 decimal places, I often preferred to use the approximation of 355/113, which is good to 6 decimal places and easier for multiplication and division without a calculator.

[Tim Streater]

I had the advantage of being interested in reading. Not just Thomas the Tank Engine at 8 years old but all the Hornblower books too. And I was given a readable scientific encyclopedia the following year which had lots of interesting facts in it. Plus I knicked my brothers 6th form prizes which were also books.

[Tim Streater]

Or as it might be, above.

[Tim Streater]

Well that's good to hear. We were doing in infants school.

[Jonathan Harston]

Well, at 20% it's easy. Move the digits to divide by ten, double it. Only slighty easier than 15%, divide by ten, add on another half. 17.5% was the fiddly one, as it was divide by ten, half it, half it again, add running total.

[mechanic]

What is this pi, and where does it come from? An intelligent question that kids doing GCSE maths might ask. A teacher replying "3.142..." is missing the point, and probably unable to answer the inevitable follow-up "why?". This number crops up so frequently in expressions that they really ought to be properly prepared for it. The teacher quoted above is on the right track.

[S Viemeister]

Yes, reading will do it!

We read to the kids from infancy, and taught them to read, as well as basic arithmetic (including fractions) before they started school.

They've continued to educate themselves.

We also taught them how to use tools.

[whisky-dave]

For us it's a small computer that when programmed can do many things like Dim an LED ;-)

[Tim Lamb]

I remembered which is quite a measure of achievement!

When we moved on to circular areas, disc and annulus, he brought in an electromagnet turned on his lathe. The coil, energized by a 6V dry battery, fitted in a circular recess. The idea being that magnetism retaining the cover plate would be most effective if the inner and outer areas were the same.

Hooks, ropes and two burly rugby players demonstrated just how effective this was:-)

[Andrew]

People without electricity probably don't need to carry out complex maths. The ancient civilisations who built Stonehenge, Machu Pichu and other carefully aligned structures didn't have slide rules either (that we know about)

[Max Demian]

#Don't know what a slide rule is for# (Sam Cooke)

I wonder if they are told logs were "discovered" (by Napier) rather than "invented" (as useful things).

Solar powered calculators. If there's no light you won't be able to use your slide rule.

[Max Demian]

Can't you just forget to tell them which spiders are dangerous?

[Andrew]

[Max Demian]

Do they still teach up to 12x? Nowadays only 2-9 is required.

[Joe]

Yes, but powers don't have an obvious use, either. Most people don't go beyond squares in their lifetimes. It's really only science and engineering that have real uses for exponentials and logarithms. And mathematicians, of course.

But thinking logarithmically is useful, as is knowing how decibels and compound interest work.

[Andy Burns]

Aren't (most?/all?) of those fake, i.e. the solar cell isn't even connected to charge the battery

[S Viemeister]

I had one for years (a freebie from a trade show). It worked perfectly, maybe still does, but I lost it somewhere.

[Andrew]

My Sharp EL-545 "Solar Cell Scientific calculator" does not work in low light.

I have had it for 35 years and have never changed the battery (if there is one).