Ask Uncle Colin: How do I multiply big numbers together? | Colin

Ask Uncle Colin is a chance to ask your burning, possibly embarrassing, maths questions — and to show off your skills at coming up with clever acronyms. Send your questions to and Uncle Colin will do what he can.

Dear Uncle Colin,

How do you multiply big numbers like $2158 \times 1812$? I try to do it using the column method or the grid, but I always make mistakes.

— A Desperately Desired Error Reduction

Hi, ADDER, and thanks for your message!

I’ve been playing with something midway between the grid and the column recently, as it happens. I’ll show…

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