15+s/3-6=13

Question

this math problem has to equal 13 what is the missing number?

Answer 1

15 +s/3 -3 = 13

multiply by 3 to get

45 + s -9 = 39

combine like terms

s = 39+9 -45 = 3

check the answer, replace s by 3

15 +3/3 -3 = 15+1-3 = 16-3 = 13 It works