MATH TRICK - DIVISIBILITY BY 3

To determine if a number is divisible by 3, use this simple trick:

Divisibility Rule for 3

1. Sum the Digits: Add all the digits of the number together.

2. Check the Sum: If the resulting sum is divisible by 3, then the original number is also divisible by 3.

Example

• For the number 123:
  1. Add the digits: $1 + 2 + 3 = 6$.
  2. Check if 6 is divisible by 3: Yes, because $6 \div 3 = 2$.

So, 123 is divisible by 3.

Another Example

• For the number 456:
  1. Add the digits: $4 + 5 + 6 = 15$.
  2. Check if 15 is divisible by 3: Yes, because $15 \div 3 = 5$.

So, 456 is divisible by 3.

This method provides a quick and effective way to check for divisibility by 3.