What is the equation for finding a number that is X% less than another number? I know this seems like a juvenile question, but for some reason I can't recall how to do this.
Lets say I want to find 87 reduced by 99.75%. What is the equation to do that?
Thanks!

A simple formula for this is: $$ \text{ New Number } = \text{ Old Number } \times \left(\frac{100 - x}{100}\right)$$
In general if a number is increased or decreased by $x\%$ then the new number is given by: $$ \text{ Old Number } \times \left(\frac{100 \pm x}{100}\right)$$
