Percents
Lessons in this chapter
About Percents
Percents is the applied end of the ratio work, and it is the topic most likely to come up in a child’s life outside the classroom.
Understand the Meaning of Percents fixes the definition: a percent is a ratio out of 100, so 35% is 35 per hundred. Everything else in the chapter follows from that one sentence.
Express Percents as Fractions and Ratios and Convert Fractions and Ratios to Percents work the conversions both ways, and Relate Fractions, Decimals, Ratios, and Percents puts all four forms side by side. A half, 0.5, one to two and 50% are the same thing in four notations, and moving between them fluently is the point.
Find Part Whole and Percent of a Quantity covers the three questions a percent problem can ask: find the part, find the whole, or find the percent. Kids usually meet only the first, which is why the second and third catch them out.
Solve Applied Problems on Percents brings in discounts, tips, tax and interest. The one worth practicing is working backwards from a sale price to the original, since that is a find-the-whole problem wearing everyday clothes.
Every lesson in Percents opens as a 6th grade math worksheet in the page, six of them in all. Find Part Whole and Percent of a Quantity and Solve Applied Problems on Percents are the two worth spending time on, and their practice questions are worked one at a time and marked as you go. Free to try, with no login needed for your first 3.
Frequently asked questions
Understand the Meaning of Percents fixes the definition that everything else follows from, a percent is a ratio out of 100. Express Percents as Fractions and Ratios and Convert Fractions and Ratios to Percents work the conversion in both directions, and Relate Fractions, Decimals, Ratios, and Percents puts all four notations side by side so a half, 0.5, one to two and 50% are seen as one thing. Find Part Whole and Percent of a Quantity covers the three questions a percent problem can ask, and Solve Applied Problems on Percents brings in discounts, tips, tax and interest. The chapter sits in the Common Core domain Ratios and Proportional Relationships (6.RP), where percent is treated as a rate per 100.
A ratio out of 100. 35% means 35 per hundred, which is 35 over 100 as a fraction and 0.35 as a decimal.
Write it as an equivalent fraction with a denominator of 100, or divide the top by the bottom and multiply by 100. Three quarters becomes 75 over 100, so 75%.
Find the part, find the whole, or find the percent. Most practice covers only the first, which is why the other two cause trouble.
It is a find-the-whole problem. If an item is 20% off and costs $40, then $40 is 80% of the original, so the original is 40 ÷ 0.8, which is $50.
They are four notations for the same thing. A half, 0.5, one to two and 50% all describe the same relationship.