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Percentages of Numbers

Use the 10% anchor to quickly find any standard percentage.

When to use

Calculating 10%, 20%, 25%, 30%, 40%, 50%, 60%, 75%, 80%, 90% of a number.

Steps

  1. 1.Find 10% by dividing by 10
  2. 2.Scale to the target percentage
  3. 3.For 80%: it's easier to calculate 100% - 20%

Example: 20% of 1,100

10% of 1,100 = 110

20% = 2 x 10% = 2 x 110 = 220

Mental approach

Anchor on 10%, then multiply. For 80%, subtract 20% from the total.

Pen & paper approach

Write 10% on the side, then build up to the target percentage.

Tips

  • •25% = divide by 4
  • •75% = 3/4 or 50% + 25%
  • •80% = 100% - 20% (often faster)
  • •For 60%: find 50% + 10%

Try it yourself

30% of 800

75% of 1,200

60% of 3,000,000