Divide the amount of decrease by the original amount. Generally the given subject is an expression like an equation or a fraction. To go down in value.
For example if you are looking for the percent of decrease from 9 to 6 the original amount is 9 and the final amount is 6.
Now it does get somewhat confusing with negative numbers. The multiplier is often written first but the position of these numbers does not really matter. Multiplier is the number that tells how many times a multiplicand should be multiplied. A letter used to represent a numerical value in equations and expressions.