This is the conundrum.
Processing left to right, 7-7 = 0, 0x0 = 0, 0 + 7 = 7.
However, Americans, and I guess some others are taught that the order of processing is PEMDAS. The order is PEMDAS: Parentheses, Exponents, Multiplication, Division (from left to right), Addition, and Subtraction (from left to right).
So, doing multiplication first, 7 x 0 is 7. This makes the question 7 - 0 + 7, resulting in 14.
So a simple sum here results in 7, but in America it is 14. How does that work? incidentally, putting this sum into the calculator on your iPhone gives the answer 14.