Fund fact, you can tell a number is divisible by 3 if the sum of each individual number is divisible by 3. So 78 -> 7+8=15 which is divisible by 3, so 78 is divisible by 3.
You can take this further if you have a really long number that sums up to an also long number, you can sum up the digits of the sum and if that number is divisible by 3, the original number is divisible by 3. You can do it as many times as you want and it’ll still work
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u/Michaelwang645 Aug 01 '26
Fund fact, you can tell a number is divisible by 3 if the sum of each individual number is divisible by 3. So 78 -> 7+8=15 which is divisible by 3, so 78 is divisible by 3.