It really depend what number, or what type of number you are multiplying, it's kind of like multiplication you're just doing it backwards. Say that you were trying to divide 20 by 5 you think in your head OK five times what equals 20 and your answer would be four because 5×4 is 20 that's the easiest way to think of it that did not help you with your question tell me in the comments and I will find a better way to explain it.
