You can the fractions of the problem with denominators (the bottom numbers). Change the denominators to ten.
1/2 = 5/10
4/5 = 8/10
Then you add those two fractions.
5/10+8/10 = 13/10= 1 3/10
Then you add your two whole numbers
42+37= 79
Then add the fraction and whole number together
79+1 3/10= 80 3/10 miles
