Write a number that is a rational number, but not an integer.

Explanation:

Pick any two numbers you want as long as they don't divide to form an integer. For instance, picking 14 and 7 divides to 14/7 = 2 which is an integer. So this pair of values won't work.

In this case, 2 and 3 don't divide to form an integer. We can see this through using a calculator

2/3 = 0.667 approximately

Note: The denominator can never be zero. The numerator can be zero, but a zero numerator leads to an integer, so you'll have to ignore zero entirely for this problem.