Welcome to the money chapter — and here is the trick that carries the whole thing: read the unit before the number. Plain dollars ($\$24$) are a total — money, full stop. Dollars wearing a slash ($\$6/\mathrm{kg}$) are a rate — money per something, and the slash is how it tells you. Kilograms with no dollars in sight ($2.5\ \mathrm{kg}$) are a quantity — the stuff itself.

And a percent? The % sign is a unit too — the per-hundred unit. 25% is not 25 dollars and not 25 kilograms: it is 25 out of every hundred of whatever it touches. That is its superpower and its trap in one: a percent means nothing until you know what it is a percent OF. No calculating this lesson — just look at each number's outfit and name it. The units will do the pointing all chapter long.