You need to add the whole numbers first, and then you add the fractions.
3 + 2 = 5
To add the fractions with unlike denominators, you must find the common denominator between the two. You do this by find the least common multiple between the two. When you list the multiples of both 2 and 8, you find the least multiple they have in common is 8. Since one of fractions has an 8 as the denominator, we can leave it alone. With 1/2 we can changin the denominator by finding out how times 2 goes into 8. It goes in 4 times, and we then multiply 4 times the numerator 1. We get 4.
3/8 + 1/2 = 3/8 + 4/8 = 7/8
The answer is 5 7/8