Percentages- 6th Grade Math Practice Guide
What Are Percentages? The Basics You Need to Know
Let's get one thing straight: a percentage is just a fraction out of 100. That's it. 50% means 50 out of 100. 25% means 25 out of 100. Once you understand this, percentages stop being scary.
Think of it like cutting a pizza into 100 slices. If you eat 30 slices, you've eaten 30% of the pizza. Simple.
Why Percentages Matter in 6th Grade
By 6th grade, you're expected to do more than just find 10% of a number. You're working with:
- Converting between fractions, decimals, and percentages
- Solving real-world percentage problems
- Finding percent of change
- Discount, tax, and tip calculations
If any of this makes your head spin, you're in the right place. Let's fix that.
How to Convert Between Fractions, Decimals, and Percentages
This is where most students get stuck. The good news: there's one trick that makes everything easier.
The Magic Rule
Move the decimal point two places. That's it.
- To convert a decimal to a percentage: multiply by 100 (or move decimal right 2 places)
- To convert a percentage to a decimal: divide by 100 (or move decimal left 2 places)
- To convert a fraction to a percentage: divide the top by the bottom, then multiply by 100
Quick Examples
Decimal to Percentage: 0.75 = 75%
Percentage to Decimal: 45% = 0.45
Fraction to Percentage: 3/4 = 0.75 = 75%
See the pattern? The fraction 3/4 becomes the decimal 0.75, which becomes 75%. They're all the same number, just written differently.
Finding Percent of a Number
This is probably what your teacher assigns most often. Here's how to do it without guessing.
Method 1: Use Proportions
Set up this equation:
part/whole = percent/100
Example: What is 20% of 50?
part/50 = 20/100
Cross multiply: part ร 100 = 50 ร 20
part ร 100 = 1000
part = 10
Method 2: Multiply Directly
Convert the percent to a decimal, then multiply.
20% of 50 = 0.20 ร 50 = 10
Both methods give you the same answer. Use whichever feels more natural to you.
Common Percentage Problems You'll Face
1. "What percent is one number of another?"
Example: What percent of 80 is 20?
Set it up: 20/80 = x/100
20/80 = 0.25 = 25%
2. "A number is some percent of what number?"
Example: 15 is 30% of what number?
15/x = 30/100
15 = 0.30 ร x
x = 50
3. Percent of Change
New value minus old value, divided by old value, times 100.
Price went from $40 to $50.
Change = (50 - 40) / 40 ร 100 = 25% increase
Real-World Percentage Problems
Your teacher loves these because they actually matter in life.
Sales Tax
An item costs $60. Tax is 8%.
Tax amount = 0.08 ร 60 = $4.80
Total = 60 + 4.80 = $64.80
Discounts
Jacket is $80, marked down 25%.
Discount = 0.25 ร 80 = $20
Sale price = 80 - 20 = $60
Tips
Bill is $45. You want to leave 20%.
Tip = 0.20 ร 45 = $9
Total = 45 + 9 = $54
Practice Problems: Test Yourself
Try these before checking the answers below.
- Convert 3/5 to a percentage
- What is 15% of 200?
- 45 is what percent of 90?
- A $120 item has 30% off. What's the sale price?
- Your grade went from 70 to 91. What's the percent increase?
Answers
- 60%
- 30
- 50%
- $84
- 30% increase
Percentages, Decimals, and Fractions Conversion Table
Keep this handy. You'll reference it constantly until these become second nature.
| Fraction | Decimal | Percentage |
|---|---|---|
| 1/2 | 0.5 | 50% |
| 1/4 | 0.25 | 25% |
| 3/4 | 0.75 | 75% |
| 1/5 | 0.2 | 20% |
| 2/5 | 0.4 | 40% |
| 3/5 | 0.6 | 60% |
| 4/5 | 0.8 | 80% |
| 1/10 | 0.1 | 10% |
| 1/8 | 0.125 | 12.5% |
| 1/3 | 0.333... | 33.3% |
| 2/3 | 0.666... | 66.7% |
How to Get Better at Percentages
Practice is the only way to get faster. Here's what actually works:
- Drill the basics first: If converting fractions to percentages is slow, fix that before moving on
- Use mental math: 10% of any number is just divide by 10. 50% is divide by 2. Build from there
- Check your work: If 20% of 50 is 10, does that make sense? Yes, because 10/50 = 1/5 = 20%
- Don't rely on calculators: You won't always have one. Practice until you can do simple percentages in your head
Common Mistakes to Avoid
These trip up almost everyone:
- Forgetting to convert the percent to a decimal before multiplying
- Mixing up which number goes on top of a proportion
- Calculating the percent off instead of the sale price
- Rounding too early and losing accuracy
Quick Reference Formulas
Bookmark these. You'll need them.
- Percent of a number: (percent/100) ร number
- Find the percent: (part/whole) ร 100
- Find the whole: part รท (percent/100)
- Percent of change: ((new - old)/old) ร 100
Master these formulas and percentage problems stop being a problem. They become automatic.