Test 40 for Divisibility by 3

Test for Divisibility by 3:
• A Number is divisible by 3 if the Sum of the Digits in the Number is divisible by 3
Sum of the Digits in 40: 4+0 = 4
4 is not divisible by 3
Therefore, 40 is NOT divisible by 3
Note: Since 40 is not divisible by 3, it follows that 40 is also not divisible by any multiple of 3 (6, 9, 12, …)

The solution above and all other related solutions were provided by the Test for Divisibility by 3 Application.