That's not really a Physics problem. In fact, by the time you ever start learning Physics, you'll be expected to know how to solve problems like that with a pencil and paper.
I'll be honest with you ... it's not even much of a Mathemtics problem. It's just a 5th Grade exercise in Arithmetic.
You can use a pencil, a calculator, a smartphone, a big computer, or an abacus. No matter what you use to work it out, 67.786 - 32.87 = <em>34.916</em> .
If you work it in two different ways, or two different people solve it, and the two answers are different, then at least one of them is wrong, and there's a pretty good chance that both are.
The answer is the same no matter what kind of classroom you're sitting in or what subject you're studying. It's a lot like the reason why cyanide gas means "goodbye" in ANY language.