"Twenty-five percent off" is easy until the sticker price is $79.99 and you need the actual dollars off, not a vibe. The form takes a percent and a base number and returns the portion—useful for tips, sale math, budget slices, and quick homework checks when you already know the rate.
This is not "what percent is 5 of 20"—that is the two-number percent page. It is also not percent change between an old and new price; that is a different column order entirely.
25% of 80 is the default pair—20—the sort of result people still verify because mental math on 79.99 goes sideways.
Discounts, tips, and the base you multiply
Percent applies to the base you choose. Tax on a subtotal is not tax on a post-discount total unless your policy says so. A 15% tip on an $85 check is a different row than 15% of the pre-tax amount—pick the number on the receipt before you paste.
When the question is growth from 80 to 100, switch pages—percent change from 80 to 100. When you only know part and total, 5 as a percent of 20 fits better.
- Percent is of the number you typed, not "of 100" unless you entered 100.
- Sale tags sometimes stack; this form does one step.
- Round for display after you have the raw amount if a slide needs whole dollars.
The percent-of-a-number examples note is worth a skim when a memo mixes discount language. Ordinary arithmetic, not tax advice.