Repeated subtraction is a teaching method used to explain the concept of division. It is also a method that can be used to perform division on paper or in one's head if a calculator is not available and the individual has not memorized the multiplication tables.
The basic concept of repeated subtraction is to repeatedly subtract the divisor from the dividend. For example, when dividing 20 by five using the repeated subtraction method, five is repeatedly subtracted from 20 until nothing is left. Five can be subtracted four times from 20, therefore 20 divided by five is equal to four.