Percentages — review for grade 7

Before you dive into price changes, discounts, tax and interest, refresh the three core computations from grade 6.

Three core computations

Mental shortcuts

• 10 % of a number — divide by 10 (shift the decimal one place left).
• 25 % = `1/4`, 50 % = `1/2`, 75 % = `3/4`.
• 20 % = twice 10 %, 5 % = half of 10 %.

Practice examples

1. What is 25 % of 80? → `80 ÷ 4 = 20`.
2. What is 30 % of 60? → `10 % = 6`, `30 % = 18`.
3. The part is 12 and it represents 25 % — what is the whole? → `12 × 4 = 48`.

Next in grade 7

You are ready for the more advanced tasks:

• Percentages for grade 7 — introduction
• Percent change
• Discount, tax, tip and simple interest

Try it yourself (review)

• Percent of a whole number
• Find the whole from a part
• Fraction, decimal and percent