When I went to primary school in 1973, I remember our teacher bought what must have been one of the first personal electronic calculators sold in the UK. She demonstrated it to us in class, and we were all amazed at how it could instantly do the sums we were puzzling over.
Mrs. M told us the calculator had cost her £100 – a lot of money in those days. The calculator was very basic by today’s standards – it could add, multiply, divide and subtract.
If Mrs. M had continued adding and subtracting for herself, and had invested her £100 at ten percent, today it would have grown to £2,555. Not a fortune by any means, but enough to buy hundreds of advanced mathematical calculators.