The answer to your question is 17/24
First find the lcd which is 24
5/8 = Times eight by three to get 23 = And whatever you do to the top you do to the bottom = So then you would do five times three to get 15 = To create your new fraction 15/24
1/12 = Times twelve by two to get 24 = And whatever you do to the top you do to the bottom = So then you would do one time two to get 2= To create your new fraction 2/24
Then you would add 15/24+2/24= 17/24