12 1/2+ 3 3/5+ 7/4 what is my total with the least common denominator

Alright, so here's your answer.

You start by making all the fractions into improper fractions. 





and  stays the same.

Now we have to find the least common denominator, which is 20. So we have to multiply each to get 20.







Now we add all three, getting us 

Simplify, and your answer is 

Hope this helps!