Which number is NOT divisible by 9?

What are your choices?


What is your answer?

117

252
133
351

I don't have an answer I need help finding the answer.

Its 133.

Right.

Here is a little trick that works with 9 and 3

add up the digits of your number.
If that sum is divisible by 9, then so is the original number.
The same rule applies to 3

e.g.
is 12546 divisible by 3 ?
add them up to get 18
since 18 divides evenly by 3, so does 12546

notice that since 18 also divides evenly by 9, so does 12546

To find out which number is NOT divisible by 9, we need to look for numbers that do not meet the criteria for divisibility by 9.

For a number to be divisible by 9, the sum of its digits must be divisible by 9.

One way to approach this problem is to check each number from 1 to 10 and see if the sum of its digits is divisible by 9.

Let's start with 1. The sum of its digits is 1, which is not divisible by 9. So 1 is not divisible by 9.

Next, let's check 2. The sum of its digits is 2, which is also not divisible by 9. So 2 is not divisible by 9.

We continue this process until we reach 10. The sum of the digits of 10 is 1 + 0 = 1, which is not divisible by 9. So 10 is not divisible by 9.

Therefore, among the numbers 1 to 10, none of them are divisible by 9.

In general, any number that does not have a sum of digits divisible by 9 will not be divisible by 9.