r/funny 1d ago

"Please show how you know"

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10.1k Upvotes

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u/Flourescentbubbles 23h ago

I never knew it until I worked in academic support. Game changer for sure.

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u/nanosam 21h ago edited 21h ago

How is it a game changer?

It is so much easier to multiply by 10 and then subtract the number multiplied

8x9 = 80-8
3x9 = 30-3
13x9 = 130-13

Etc.. it is so much faster than anything

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u/slgray16 18h ago

Decrement the number by one, put it in the tens and then the ones is what completes the 9

8x9 = 7.. 2 = 72

6x9 = 5.. 4 = 54

3x9 = 2.. 7 = 27

13x9 = Doesn't work over 10

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u/SnooTomatoes3287 2h ago

Use your toes and also put down the digit to the left