What is the answer to a division problem called?

The result of a division is the quotient, from the Latin quotiens, meaning how many times. Each arithmetic operation has its own vocabulary, and knowing all four saves confusion when reading instructions or maths textbooks. Addition gives a sum, from addends. Subtraction gives a difference, the minuend less the subtrahend. Multiplication gives a product, from factors. Division takes a dividend and a divisor and yields a quotient, plus a remainder when the division does not come out evenly. So dividing 17 by 5 gives a quotient of 3 and a remainder of 2. Many programming languages keep these distinct with separate operators, one returning the integer quotient and another returning just the remainder, which is called the modulo. The remainder idea powers a surprising amount of practical mathematics, from telling the day of the week for a future date to the check digits that catch typing errors in account numbers.

Dividing by zero has no answer because no number multiplied by zero can give a non-zero result.