Each one of these factions have a prime number in it, so therefore, you cannot simplify any of them. Prime numbers are numbers that only have 2 factors, one and itself. So, you can't simplify any of them.
Here's why:
If you take 3/4, you can't simplify because 3 is prime. 4 is NOT prime, but to reduce, you have to be able to find a GCF, or a greatest common factor.
