The denominator of the first fraction is 1000, 1000 = 2× 2× 2× 5× 5. Obviously, 34 1 has no prime factor and cannot be reduced.

The numerator of the second fraction is 17, 17 is a prime number, and the denominator 60 is not a multiple of it, so it cannot be reduced.

The third score is the same as the second.

The fourth score is the same as the second.