What's the highest level of math you've studied?

@Nimbus I've never used an abacus but I can still remember how to use a slide-rule or log. tables!

(For anyone who might have heard of those but never used them, they were the standard, pre-calculator, tools for multiplication, division and powers arithmetic.)

@ArishMell I remember slide rules, horrid things.

@Nimbus Mmmm!

I once wanted to perform a calculation a bit too awkward for pen-and-paper (I think it involved a root of a decimal value), but I could not find my calculator anywhere.

"Ah!" thinks I, "Slide Rule!" I never thought of them as horrid but did struggle with maths.

Could not find that either - my home defies my efforts to be organised and tidy, let alone try Feng-shui or any other minimalist fad.

Nothing for it... Logarithm tables, revising the method from a worked example in the book.

Nest day I bought a new scientific calculator... the lost one turned up three weeks later, when I was looking for something else!