Percent: base value, percentage value, rate
Find the percentage value W, the rate p % or the base value G with the percent strip, the rule of three and the formula W = G · p %.
- Germany: grade 6
Guide
In percent problems three quantities belong together: the base value G (the whole, 100 %), the percentage value W (the part) and the rate p % (the share). If you know two, you can find the third.
The percent strip shows the base value as 100 %. You can work with the rule of three (Dreisatz): find 1 % first, then multiply. The formula is W = G · p %. Examples: 15 % of 80 € is 80 € · 0,15 = 12 €.
Always write the answer in a sentence ("Answer: The jacket now costs 68 €."), and check if the result is sensible: a part is smaller than the whole, and a discounted price is smaller than the old price. The difference between percent and percentage points is explained in the lessons.