The very first thing you have to do with a Mixed fraction is to turn it into a improper one. By doing that you have to multiply the mixed number by the denominator like:
7 1/6 : 7x6=42
Then your fraction is improper and looks like this: 42/6
Also add the fraction beside the mixed number to your improper fraction like this: 42/6 + 1/6 = 43/6
Do this with your other mixed fraction too and youll end up with the answer.
7x6= 42/6 + 1/6 = 43/6
6x6= 36/6 + 4/6 = 40/6
43/6 - 40/6 = 3/6
Simplify 3/6 and get 1/2
1/2 is your answer.