With this problem you will need to use the order of operations, or PEMDAS.
P= parentheses
E= Exponents
M= Multiplication
D= Division
A= Addition
S= Subtraction
There is no parentheses or exponents, so mark those out.
I am not so great with working things out like this problem, but i am sure that the person above/below did work it out correctly.
I can give you the answer though.
Answer= 25
Sorry if that answer is incorrect
Hoped this helped.... Sorta,
-Anime