Math · Topic 121 of 124
Divisibility by Three
⭐ MasteredA number is divisible by three if the sum of its digits is divisible by three. For example, 129 is divisible by three because 1 + 2 + 9 = 12, which is a multiple of three.
💡 Fun fact
The divisibility rule for three works for any size of number, even very large ones.
All about Divisibility by Three
A number is divisible by three if the sum of its digits is divisible by three. For example, 129 is divisible by three because 1 + 2 + 9 = 12, which is a multiple of three. This rule works for numbers of any size.
Even very large numbers can be tested for divisibility by three by adding up their digits, and then repeating the test if the result is still large.
🎮 Try it yourself!
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