Percent in money situations
A price tag, a bill, a paycheck and a loan all carry a percent. Which amount is each percent taken of, and is the result added on or taken off?
Where you are 3 inside
What this area is about
Most percents met outside a classroom are about money: a sale, a tax, a tip, a markup, interest on savings or a loan. Each is a percent of a base amount, so the work repeats: decide which amount is the whole, find the part, then add it on or take it off.
How these fit together
All three are procedures built on the percent equation, part = rate \times whole.
At the till. Discounts, sales tax, tips and commission take a percent of a price, a bill or a total of sales, then subtract it, add it, or pay it to the seller.
What a seller adds. Markup and margin measure one profit two ways: markup as a percent of the cost, margin as a percent of the selling price. For a seller who makes a profit, the margin is the smaller of the two.
Money over time. Simple interest is I = Prt: a percent r of the principal P for each of t years, worked out on the principal only, so earlier interest never earns interest of its own.
A path through it
None of the three depends on another, so they can be taken in any order. Each assumes percent change, and discounts and simple interest also use two percent changes in a row.
Finish here and you can check a receipt, tell a markup from a margin, and total a simple-interest loan or deposit.