Question

which number is prime 15,27,43,63,99?

Answer 1

What is 15 divisible? 27? 43? 63? 99?

Answer 2

prime means the only factors they have is 1 and itself

Answer 3

15 isnt prime because 3*5=15

Answer 4

27 isnt prime because 3*9=27

Answer 5

99 isnt prime because 11*9=99

etc

Answer 6

Hint:

When you're trying to find factors, start dividing the numbers by 2 as much as you can. Then move to 3, then 5, 7, 11, 13, etc. Teachers usually won't give you huge prime numbers.

Answer 7

9*7=63 so 43 must be prime

Answer 8

Thank you! @AbdullahM @rebeccaxhawaii

Answer 9

It was my pleasure!

Answer 10

Also, a tip:

Don't get confused with squares and primes. 9 is not a prime number because it can be broken down to 3 * 3.