Explain the different ways that you can use multiplication to estimate and solve division problems

Well one way that you can use multiplication to estimate and solve division problems is that when you are dividing a smaller number or any number into another number for example... 12/324 you can multiply what times 12 equals 324. That or use a calculator if it is aloud I may add. Sometimes it is easier to do it that way then doing out all the horrible long steps making it harder to do.