Arithmetic (Beginner) · Quick Reference

Percentages Cheat Sheet

Arithmetic (Beginner) · Lesson 10/21

In one line: a percentage expresses a number as a part of 100. It is one of the most commonly used tools in daily life, from discounts to exam scores.

Key Ideas

1Meaning of Percent. 'Percent' means 'per hundred'. 25% means 25 out of every 100.

2Converting Percent to Decimal. Divide by 100 (move the decimal point two places left).

3Converting Decimal to Percent. Multiply by 100 (move the decimal point two places right).

4Finding a Percentage of a Number. Multiply the number by the percentage written as a decimal.

5Percentage Increase/Decrease. Find the difference, divide by the original value, then multiply by 100.

Worked Examples

Find 20% of 150.

Convert 0.45 to a percentage.

45%

A shirt's price rose from $40 to $50. Find the percentage increase.

25% increase

Formulas

Percent of a number = (Percent/100) x Number

Percentage change = (Change/Original) x 100

Practice Yourself

Find 50% of 80.

Convert 3/4 to a percentage.

75%

Convert 60% to a decimal.

0.6