What is 4/6+1/3 can y’all tell me this is for homework and I can’t seem too figure it out

7. carlos martin received a statement from his bank showing a balance of $56.75 as of march 15. his checkbook shows a balance of $87.37 as of march 20. the bank returned all the cancelled checks but two. one check was for $5.00 and the other was for $13.25. how much did carlos deposit in his account between march 15 and march 20?