What is a correct way to check the answer to this equation:

4,112 ÷ 5 = 822 remainder 2

Achemist has 200 ml of a 10% sucrose solution. she adds x ml of a 40% sucrose solution. the percent concentration, y, of the final mixture is given by the rational function: the chemist needs the concentration of the final mixture to be 30%. how many milliliters of the 40% solution should she add to the 10% solution to get this concentration?

3382-299=3383- ? fill in the blank?

Is a positive integer raised to a negative power always positive