We use percents in decimal form to multiply it with the price. We convert percents into decimals by dividing the percent number by 100. For example, 78% divided by 100 becomes 0.78.
There are two ways to look at it:
For finding the price we pay during a sale, we focus on the percent we pay. If 60% off is the sale, then we spend 40% or 100-60=40. 40% is 0.40. Multiply that by p an unknown price and we have 0.4p.
We can find the percent off by multiplying the price by the percent conversion. So 60% is 0.60. Then subtract it from the original price to find the leftover that we pay. This is p-0.6p.
