How to know if a number is divisible by 3

Ever see people look at a number and they can immediately tell you if the number is divisible by 3 or not? Well this is how you do it! Add all the digits and if that is divisible by 3, then the whole number is divisible by 3. Check out my other videos on divisibility rules:

1-4: https://rumble.com/vjq9p9-caveman-chang-demonstrates-divisibility-rules-aka.-another-math-shortcut.html
5-12: https://rumble.com/vkgyot-caveman-chang-shorcuts-with-divisibility-rules-part-2.html

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