I like doing maths in my head

Ppl like how do you do those big multiplications in your head? Take 13 times 17. 13 times 10 is 130 13 times 7 is 70 plus 21 so 91. And 91 plus 130 is 231. So 13 times 17 is 231. 🤷🏼 It entertains myself.

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JimboSaturn · 56-60, M

That's how I do it too! I can only multiply two, two-digit numbers well though because I forget the numbers I've already worked out, more practice I guess!

pride49 · 31-35, M

@JimboSaturn I gotta break them down into 10s, 100s etc before adding the result
Next is mind division

JimboSaturn · 56-60, M

@pride49 Yes just like 10s I start with 100s . I guess what we are doing is "foiling" they used to call it?

pride49 · 31-35, M

@JimboSaturn I always liked the lattice method of paper multiplication. Gives an almost drawing atmosphere to it.

pride49 · 31-35, M

@JimboSaturn foiling?

JimboSaturn · 56-60, M

@pride49 back in school they called it that in my day : Foil
https://en.wikipedia.org/wiki/FOIL_method

This is not exactly what we do

JimboSaturn · 56-60, M

@pride49 I just looked that up, I've never seen that before, cool! We learnt it by the carry over method