Hi there!
Yes, if the two fractions are less than one, their sum can be greater than one. Take the example of 3/4 and 3/4. It is less than 1, but has a sum if 1 1/2.
However, their sum cannot be greater than 2. For that to happen, there would have to be a sum of at least 1 and 1, which are not fractions.
Hope this helps :)