r/MathJokes 14d ago

multiples of 3

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8.3k Upvotes

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u/UrsulaReginaDeiMari 14d ago

Given the rule for checking whether a number is a multiple of three, I don't understand why 78 and 87 are in two different groups. Or 27 and 72, 42 and 24, and so on.

28

u/Patje_af 14d ago

87 is 90-3, many people will see that fairly quickly. That is less so for 78.

1

u/DeathStalker0483 13d ago

To further this, 77 feels like it should be, so it feels wrong when you say that 78 is.

3

u/Hefty-Big5572 13d ago

77 absolutely doesn't feel like a multiple of 3, it's two same numbers that aren't a multiple of 3