A Percent Scales a Base

You'll learnto find the base a percent scales, multiply, and report the member the question named.

A percent scales a base, so the first move is finding the base and the second is multiplying, never subtracting the percent as if it were dollars. Points leak in taking the percent of the wrong base, treating a percent as an absolute number, and reporting the change when the value was asked.

8 STEPS · 6 QUICK CHECKS · find the base, then multiply · v3

percent × base

Before you start

What you're looking at

A percent bar for a $140 ticket at 25% off, keeping 75%, with 140 × 0.75 = 105 shown, beside a plan card.

The question

What is the sale price of a $140 ticket at 25% off — and what is the base?

Watch for

The bar fills to 75%; watch that the ticket keeps 75% of its price, so you multiply, never subtract 25.

What the symbols mean

The full bar is the base ($140); the filled part is 75% kept after the discount; the crossed-out line is the tempting wrong move.

Keep these apart

One computation makes three different amounts — the original $140, the percent amount (25% of it, $35 off), and the final sale price, $105. Three ways points leak from mixing them up: the wrong base, a percent read as dollars, and the change handed back when the value was asked. The discount is not the price.

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