mathematics solves problems by using logic. one of the main tools of logic used by mathematicians is deduction. deduction is a special way of thinking to discover and prove new truths using old truths. to a mathematician, the reason something is true (called a proof) is just as important as the fact that it is true, and this reason is often found using deduction. using deduction is what makes mathematics thinking different from other kinds of scientific thinking, which might rely on experiments or on interviews.