I'm so good at math I don't use a calculator... or paper.
My math teacher made us use paper... I could do half the problems in my head, but she wanted our work worked out on the paper so she didn't think we were cheating because she put the answers on the school website... She was a horrible teacher.
That's kind of well, not right, since we use calculators to solve problems.
My teacher only cares on how you do it, the answer is less of the concern