Percent Calculations
Grade 6 · Math · Study Guide
Learn how to calculate percentages, find the percent of a number, and solve real-world percent problems.
A percent means 'per hundred.' The symbol % represents percent. For example, 45% means 45 out of every 100. Percents are used constantly in everyday life — in sales, taxes, tips, and test scores.
To find a percent of a number, convert the percent to a decimal by dividing by 100, then multiply. For example, to find 30% of 80: 30 ÷ 100 = 0.30, then 0.30 × 80 = 24. Alternatively, you can write the percent as a fraction: 30% = 30/100 = 3/10, and then multiply.
To find what percent one number is of another, divide the part by the whole and multiply by 100. For example, what percent is 15 of 60? 15 ÷ 60 = 0.25, and 0.25 × 100 = 25%.
You can also find the whole when you know the percent and the part. If 20% of a number is 8, divide 8 by 0.20 to get 40.
Real-world applications include calculating a 15% tip on a restaurant bill, finding the sale price after a 25% discount, or determining what score you need to pass a test. Mastering percents makes you a stronger math thinker and a smarter decision-maker in everyday situations.
Key terms
- Percent
- A ratio that compares a number to 100; written with the % symbol
- Part
- The portion of the whole being described in a percent problem
- Whole
- The total amount in a percent problem
- Decimal Equivalent
- A percent converted to a decimal by dividing by 100; e.g., 45% = 0.45
- Discount
- A reduction in price, often expressed as a percent off the original price
- Tax
- An additional percent added to a price, such as sales tax
Flashcards
- 25% as a decimal
- 0.25
- 50% as a fraction
- 1/2
- Find 10% of any number
- Divide the number by 10; e.g., 10% of 80 = 8
- Formula: percent of a number
- Percent ÷ 100 × Whole = Part
- Formula: what percent is part of whole?
- Part ÷ Whole × 100 = Percent
- What is 15% of 60?
- 0.15 × 60 = 9
- 20% discount on $50
- Discount = 0.20 × 50 = $10; Sale price = $40
- 75% as a decimal
- 0.75
Questions
What is 25% of 200?
- 25
- 50
- 75
- 100
Show answer
Answer: 50
25% of 200 = 0.25 × 200 = 50
What percent of 50 is 10? ___
Show answer
Answer: 20%
10 ÷ 50 = 0.20 × 100 = 20%
To convert 60% to a decimal, you divide by 100 to get 0.60.
Show answer
Answer: True
To convert any percent to a decimal, divide by 100; 60 ÷ 100 = 0.60
A shirt costs $40. It is on sale for 20% off. What is the sale price?
- $8
- $28
- $32
- $38
Show answer
Answer: $32
20% of $40 = $8 discount; $40 − $8 = $32
If 10% of a number is 7, the number is ___.
Show answer
Answer: 70
If 10% = 7, then 100% = 7 × 10 = 70
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