When adding fractions with the same denominator ( the bottom) you just add the numerator ( the top). The 3 outside the first equation is just 3 so you dont do anything
3 + 2/10 + 3/10 + 4/10 = 3 + 9/10
Answer : 3 9/10
3 (in the first box) and 9/10 in the second one