What Percent Is It
Part of the Decimals, Percents & Ratios section of Coddy's Pre-Algebra journey. Lesson 29 of 56.
Sometimes you know the part and the whole and want the percent. You scored 12 out of 20 on a quiz: what percent is that? The part over the whole is the fraction 12/20. A percent counts hundredths, so multiply the fraction by 100: (12/20) × 100 is 60.
On the board, pick the letter p for the percentage, the number in front of the percent sign. Write p = (12/20) × 100, then p = 60, which says 60%. Do not write the percent sign after it: on the board 60% is the number 0.6, a different value from 60.
Why does multiplying by 100 work? 12/20 is 0.6, and 0.6 is 60 hundredths. Multiplying by 100 just counts those hundredths for you.
Challenge
Mia got 18 of the 24 questions right. What percent is that? Find the percentage p (p = 40 would mean 40%). Write p equal to the calculation, then work it out.
Test yourselfThis lesson includes a short quiz. Start the lesson to answer it and track your progress.
Test yourselfThis lesson includes a short quiz. Start the lesson to answer it and track your progress.
All lessons in Decimals, Percents & Ratios
4Dividing Decimals
Dividing by a DecimalDividing by 10 and 100Dividing by a Whole NumberUnit PriceRecap: Dividing2Adding Decimals
Adding DecimalsSubtracting DecimalsNegative DecimalsMaking ChangeRecap: Add and Subtract3Multiplying Decimals
Multiplying DecimalsTimes 10, 100, 1000Bigger ProductsBuying by WeightRecap: Multiplying6Percent Basics
What Percent MeansPercent of a NumberPercent as a DecimalWhat Percent Is ItRecap: Percent Basics