How many distinct prime factors does 56 have?
I know that 56 is divisible by 2, so I can write it as 2 times something. That something is 28, which is also divisible by 2, so I can write it as 2 times 14. 14 is also divisible by 2, so I can write it as 2 times 7. So, 56 is equal to 2 times 2 times 2 times 7, or 2^3 times 7. That means it has two distinct prime factors: 2 and 7. 