Understanding Percents

Pre-Algebra · Axiom Academy

A percent is just a count out of 100 — and that one idea connects fractions, decimals, and "how much of an amount." 1. A Percent Is a Count Out of 100 "Percent" means per 100 . The grid below is 100 cells — one whole. Watch it fill to 25 cells: 25 filled out of 100 total is 25 percent. The symbol is shorthand for " ." the % symbol just means "divide by 100" 2. Percent, Fraction, Decimal — One Value Percents, fractions, and decimals are three names for the same amount. Shade part of the bar and read it three ways at once : the percent, the fraction over 100, and the decimal all move together because they all describe the same shaded portion. 3. Common Percents Worth Knowing A handful of percents land on clean fractions. Watch a marker sweep the bar and stop at the landmarks — each stop names the percent and the simple fraction sitting at that spot. Knowing these by sight makes mental math fast. A quarter — one of four equal parts. The whole thing — all 100 out of 100. 4. Taking a Percent OF an Amount "Find of 50 " means: take the part of 50 that the percent picks out. Because a percent is a fraction, "of" is just multiply by the decimal: , so of . The bar below holds 50; the shaded part to the left of the cut is the answer. You've seen what a percent really is — a count out of 100 — and how that single idea ties together fractions, decimals, and taking a part of an amount. Scroll up to revisit any step.

This is the written version of the interactive lesson above. See the full Pre-Algebra course.