Why you divide instead of subtracting

If a value has already increased, the final number contains the original amount and the added percentage. To recover the start, divide by the full multiplier, such as 1.20 for a 20% increase.

Common use cases

This comes up with marked-up prices, salary adjustments, population growth, tax-added totals, and any reverse percentage question where the ending value is known first.

Quick check

After finding the original value, multiply it by the growth factor again to make sure it returns to the final value shown in the summary cells.