courses › Fractions, Decimals & Percents

Find the percent, the whole, or the price before a discount.

In your head, jot if needed · no calculator why?

Learn first (about 3 minutes)

Opens at level 13.

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Builds on: Percents (not open yet)

skills · practice stats

From rounds of this course only: box, review and trial answers are left out. Once a skill has 40 tries, it compares your first 20 tries with your last 20.

• What percent? par 9 s not tried yet

  worked example

  70 is what percent of 200?

  Answer: 35%

  1. Part ÷ whole: 70/200 = 7/20 = 0.35 = 35%.

• Find the whole par 11 s not tried yet

  worked example

  19 is 20% of what number?

  Answer: 95

  1. 20% is one fifth, so the whole is 5 × 19 = 95.

• Percent change par 11 s not tried yet

  worked example

  A price rises from $500 to $525. What is the percent increase?

  Answer: 5%

  1. Change ÷ starting value: 25 ÷ 500 = 0.05 = 5%.

• Price before the discount par 12 s not tried yet

  worked example

  After 25% off, a lamp costs $198. What was the original price?

  Answer: $264.00

  1. $198 is 75% of the original, so divide by 0.75: 198 ÷ 0.75 = $264.

rest ladder

Win 3 of your last 4 rounds and the course rests. A win is 90% right, within 2× the round's par. Pass the review when it comes back and the next rest is longer.

1. 1 day
2. 3 days
3. 7 days
4. 14 days
5. 30 days
6. 60 days
7. mastered · every 90 days

your rounds

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