Judge which is an integral and which is a fraction 1 / x, X / 3, 3 / m, 3 / x, which is an integral and which is a fraction?

Judge which is an integral and which is a fraction 1 / x, X / 3, 3 / m, 3 / x, which is an integral and which is a fraction?

An integral is an algebraic expression without letters in the denominator
A fraction is an algebraic expression in which the denominator contains letters
Then you can distinguish now!
The first, the third and the fourth are fractions. There are no letters in the second denominator, so they are integers