The sum is 4 and 17/20. first, you have to create a common denominator. the least common multiple of 4 and 10 is 20, so I used that. since 10 is multiplied by 2 to achieve, twenty, we also multiply 1 by 2, which makes 3 and 2/10 4 on the other hand, is multiplied by 5 to achieve 20, so we multiply 3 by 5 also, which is 15. from there, we have 3 2/20 + 1 15/20, which equals 4 17/20.