12 + 7 - 3 - 2
There are many ways to use mathematical symbols to make 3, 7, 12, and 2 equal 15. Here are a few examples:
3 + 7 + 2 + 3 = 15
(Add the first three numbers together, then add one of the 3's to get 15)
12 - 7 - 3 + 13 = 15
(Subtract 7 and 3 from 12 to get 2, then add 13)
2(7 + 3) - 12 = 15
(Add 7 and 3 together, multiply by 2, then subtract 12)
7(2) + 3 + 3 - 4 = 15
(Multiply 7 by 2, add 3 and the other 3, then subtract 4)
These are just a few examples - there are many other ways to use mathematical symbols to make these numbers equal 15!