@schappi That's how I multiply in my head. How do people who actually know maths do it?
@schappi I work better with multiples of 10. To use your own example, I would do:
30*7 = 21*10 = 2108*7 = 56210 + 56 = 266
If I used 5 (10/2), I would have to divide and I'm not good at that, to be honest. Same with subtraction.
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for example 38*7 is 38*(10/2+2) so we have
38*10/2=380/2=190
38*2=(40-2)*2=80-4=76
190+76=190+80-4=200+80-4-10=280-10-4=270-4=266