Increasing the number of solution steps is sometimes helpful [sometimes overwhelming and confusing].  By clicking on the 'Options' tab and selecting 'a lot of steps' it makes it clear that '7' is a common factor in both the denominator and the numerator and hence '7' is cancelled. 

The appearance 2*2 rather than '4' is simply a feature of the software, in that all integers are prime factored. Prime factorization is a good practice because it helps identify common terms in the numerator and denominator of any fraction and therefore ensures that cancellations are properly recognized.

For example, when working with fractions it is obviously apparent that the "sevens" in both the numerator and denominator may be cancelled while it may be less obvious that "91/28" has any cancellations at all. After expressing 91/28 in its prime-factored version, (7 * 13) / (2*2 * 7), there is an obvious cancellation.