The lesson
This lesson teaches Percent Problems. Read each section in order, work through every example on paper, then use the practice problems and quick check at the bottom.
Percent means 'per 100'
To find a percent of a number, change the percent to a decimal and multiply. 25% = 0.25, so 25% of 80 is 0.25 × 80 = 20.
Percent means "out of 100." 25% is 25 per hundred, or 25/100, or 0.25 depending on what form helps you calculate.
To find a percent of a number, convert the percent to a decimal and multiply. To find what percent one number is of another, divide and multiply by 100.
Tax, tip, discount, and markup
When you study tax, tip, discount, and markup, slow down and write one example in your notebook without looking at the screen. That active step is what turns reading into learning.
- 1Find the percent amount (the tax, tip, or discount).
- 2For tax, tip, or markup, add it to the original.
- 3For a discount, subtract it from the original.
Percent means "out of 100." 25% is 25 per hundred, or 25/100, or 0.25 depending on what form helps you calculate.
To find a percent of a number, convert the percent to a decimal and multiply. To find what percent one number is of another, divide and multiply by 100.
A $40 shirt is 30% off. What is the sale price?
- 1Discount = 0.30 × 40 = 12.
- 2Sale price = 40 - 12 = 28.
- 3A shortcut: pay 70%, so 0.70 × 40 = 28.
Percent means "out of 100." 25% is 25 per hundred, or 25/100, or 0.25 depending on what form helps you calculate.
To find a percent of a number, convert the percent to a decimal and multiply. To find what percent one number is of another, divide and multiply by 100.
Why this matters
Percent Problems shows up constantly in solve tax, tip, discount, markup, and percent-change problems. It also connects to what you will see on homework, quizzes, and the next unit in this grade.
Teachers often move fast in class. This page is here so you can pause, re-read, and practice until the idea feels familiar, not just until you have memorized a rule for one day.
Common mistakes to avoid
Rushing to the answer without writing steps. Middle-school math rewards clear work, and you catch errors earlier when steps are visible.
Mixing up similar ideas from the same topic. If two terms feel alike, make a two-column note: what is the same, what is different, and one example of each.
Key ideas from this lesson
- Percent means 'per 100'
- Tax, tip, discount, and markup
- Find the percent amount (the tax, tip, or discount).
- For tax, tip, or markup, add it to the original.
- For a discount, subtract it from the original.
Video walkthrough
Finding a Percent of a Number
Two methods for finding a percent of any amount.
Watch on YouTubePractice
For each problem: write your work in the box, type your answer, and check it. If you are stuck, reveal the solution one step at a time. Do not skip straight to the final answer.
Exercise 1
Try it yourselfFind 18% of $250.
Step-by-step solution
- 118% = 0.18.
- 20.18 × 250 = 45.
- 318% of $250 is $45.
Exercise 2
Try it yourselfA $80 item is discounted 25%. What is the sale price?
Step-by-step solution
- 1Discount = 0.25 × 80 = 20.
- 2Sale price = 80 − 20 = 60.
- 3Shortcut: pay 75% → 0.75 × 80 = 60.
Exercise 3
Try it yourselfA meal costs $42. You leave a 15% tip. What is the total bill?
Step-by-step solution
- 1Tip = 0.15 × 42 = 6.30.
- 2Total = 42 + 6.30 = 48.30.
Exercise 4
Try it yourselfA price rises from $120 to $150. What is the percent increase?
Step-by-step solution
- 1Change = 150 − 120 = 30.
- 2Percent change = 30 ÷ 120 × 100 = 25%.
Exercise 5
Try it yourselfA $95 jacket has 8% sales tax. What is the total cost?
Step-by-step solution
- 1Tax = 0.08 × 95 = 7.60.
- 2Total = 95 + 7.60 = 102.60.
Quick check
Answer all questions. Retake the quiz until you feel confident before moving on.
Percent Problems
Question 1 of 5
A $60 jacket is marked up 20%. What is the new price?