Percentages without panic

Percentage of an amount, increases and decreases, percentage change and working back to the whole. About 9 minutes, KS3 / GCSE.

What you will do

  1. What "percent" means. Percent means "out of 100". So 25% is 25 out of 100, which is the fraction 25100 = 14. Every percentage problem is really a fraction problem.
  2. A percentage of an amount. To find a percentage of an amount, turn the percentage into a decimal (÷ 100) and multiply. Watch the engine do it, then try a quick one.
  3. Increasing by a percentage. To increase 80 by 15%, find 15% of 80 and add it on. The shortcut is to multiply by 1.15 in one step.
  4. Percentage change. Percentage change compares the change with where you started: changeoriginal × 100.
  5. Working back to the whole. If you know a part and its percentage, find 1% by dividing, then multiply by 100 to get the whole.

Loading SumClash…