For most of us, the way we multiply relatively small numbers is by remembering our times tables – an incredibly handy aid first pioneered by the Babylonians some 4,000 years ago.
But what if the numbers get bigger? Well, if the figures get unwieldy – and assuming we don't have a calculator or computer, of course – most of us would then turn to long multiplication: another useful trick we learn in school, and a trusty technique for multiplying basically any two numbers together.
There's just one problem with long multiplication. It's slow.