Compare Fractions | Fifth Grade
Complete Notes & Formulas
1. Graph and Compare Fractions on Number Lines
Definition: A number line helps visualize fractions and compare their values. Fractions further to the right are greater, and fractions further to the left are smaller.
📝 Steps to Graph Fractions on a Number Line:
- Step 1: Draw a number line with two whole numbers (usually 0 and 1)
- Step 2: Divide the space between 0 and 1 into equal parts based on the denominator
- Step 3: Count from 0 according to the numerator and mark that point
- Step 4: Label the point with the fraction
🔑 Comparing on Number Lines:
Fractions on the RIGHT are GREATER →
← Fractions on the LEFT are SMALLER
✏️ Example: Compare 2/5 and 3/5
On a number line divided into fifths:
0 ----[1/5]----[2/5]----[3/5]----[4/5]---- 1
• 2/5 is to the left of 3/5
• 3/5 is to the right of 2/5
Therefore: 2/5 < 3/5 or 3/5 > 2/5
2. Compare Fractions Using Benchmarks
Definition: Benchmark fractions are common fractions (like 0, 1/4, 1/2, 3/4, and 1) used as reference points to estimate and compare other fractions.
📐 Common Benchmark Fractions:
0 --- 1/4 --- 1/2 --- 3/4 --- 1
🔑 How to Use the 1/2 Benchmark:
If... | Then... | Example |
---|---|---|
Numerator < Half of Denominator | Fraction < 1/2 | 3/8 < 1/2 (3 < 4) |
Numerator = Half of Denominator | Fraction = 1/2 | 4/8 = 1/2 |
Numerator > Half of Denominator | Fraction > 1/2 | 5/8 > 1/2 (5 > 4) |
✏️ Example: Compare 3/10 and 7/8 using benchmarks
Step 1: Compare each to 1/2
• 3/10: Is 3 more or less than half of 10?
Half of 10 = 5, and 3 < 5
So 3/10 < 1/2
• 7/8: Is 7 more or less than half of 8?
Half of 8 = 4, and 7 > 4
So 7/8 > 1/2
Step 2: Compare: 3/10 < 1/2 < 7/8
Therefore: 3/10 < 7/8
💡 Quick Benchmark Checks:
- Close to 0: Numerator is very small (Example: 1/10, 1/12)
- Close to 1/4: Numerator is about 1/4 of denominator (Example: 2/9, 3/13)
- Close to 1/2: Numerator is about half of denominator (Example: 5/9, 6/13)
- Close to 3/4: Numerator is about 3/4 of denominator (Example: 6/8, 9/12)
- Close to 1: Numerator almost equals denominator (Example: 9/10, 11/12)
3. Compare Fractions and Mixed Numbers
Definition: When comparing fractions and mixed numbers, there are several strategies depending on the types being compared.
📝 Strategies for Comparing:
Strategy 1: Compare Whole Numbers First
When comparing mixed numbers, look at whole numbers first.
Example: 3 1/2 > 2 5/6 (because 3 > 2)
Strategy 2: Same Whole Numbers? Compare Fractions
If whole numbers are equal, compare the fraction parts.
Example: 4 3/5 vs 4 2/3 → Compare 3/5 and 2/3
Strategy 3: Convert to Common Form
- Use common denominators for fractions
- Convert mixed numbers to improper fractions
- Convert to decimals
✏️ Example 1: Compare 5 2/3 and 5 3/4
Step 1: Whole numbers are the same (both are 5)
Step 2: Compare fractions: 2/3 vs 3/4
Step 3: Find LCD: LCD of 3 and 4 = 12
• 2/3 = 8/12
• 3/4 = 9/12
Step 4: 8/12 < 9/12
Answer: 5 2/3 < 5 3/4
✏️ Example 2: Compare 7/8 and 1 1/4
Method: One is a fraction, one is a mixed number
• 7/8 < 1 (proper fraction is less than 1)
• 1 1/4 > 1 (mixed number is greater than 1)
Answer: 7/8 < 1 1/4
4. Put Fractions in Order
Definition: Ordering fractions means arranging them from least to greatest (ascending) or greatest to least (descending).
📐 Methods to Order Fractions:
Method 1: Common Denominator
- Find LCD (Least Common Denominator)
- Convert all fractions to equivalent fractions with LCD
- Compare numerators (smaller numerator = smaller fraction)
- Write original fractions in order
Method 2: Convert to Decimals
- Divide numerator by denominator for each fraction
- Compare decimal values
- Write original fractions in order
Method 3: Benchmark Comparison
- Compare each fraction to benchmarks (0, 1/2, 1)
- Group fractions by benchmark ranges
- Order within each group
✏️ Example 1: Order from least to greatest: 3/4, 1/2, 5/6
Using Common Denominator Method:
Step 1: Find LCD of 4, 2, and 6 → LCD = 12
Step 2: Convert to equivalent fractions:
• 3/4 = 9/12
• 1/2 = 6/12
• 5/6 = 10/12
Step 3: Compare numerators: 6 < 9 < 10
So: 6/12 < 9/12 < 10/12
Answer: 1/2 < 3/4 < 5/6
✏️ Example 2: Order from greatest to least: 2/5, 3/10, 1/2
Using Decimal Method:
Step 1: Convert to decimals:
• 2/5 = 0.4
• 3/10 = 0.3
• 1/2 = 0.5
Step 2: Order decimals: 0.5 > 0.4 > 0.3
Answer: 1/2 > 2/5 > 3/10
💡 Quick Tips for Ordering:
- Same Denominator: Compare numerators (larger numerator = larger fraction)
- Same Numerator: Compare denominators (smaller denominator = larger fraction)
- Unit Fractions (numerator = 1): Smaller denominator = larger fraction
- Near 1: If numerator and denominator are close, fraction is close to 1
Comparison Symbols Guide
Symbol | Meaning | Example |
---|---|---|
< | Less than | 1/4 < 1/2 |
> | Greater than | 3/4 > 1/2 |
= | Equal to | 2/4 = 1/2 |
💡 Memory Trick:
The symbol "opens" toward the BIGGER number!
Think of it like a hungry alligator eating the larger number 🐊
Quick Reference Chart
Method | When to Use | Key Steps |
---|---|---|
Number Line | Visual comparison needed | Right = Greater, Left = Smaller |
Benchmarks | Quick estimation | Compare to 0, 1/4, 1/2, 3/4, 1 |
Common Denominator | Precise comparison | Find LCD, convert, compare numerators |
Decimals | Calculator available | Divide, then compare decimals |
💡 Special Comparison Rules:
Same Denominators
Compare numerators
3/7 < 5/7
Same Numerators
Smaller denominator = bigger
2/3 > 2/5
Proper vs Improper
Improper > 1 > Proper
5/3 > 3/5
Mixed Numbers
Compare whole parts first
3 1/4 > 2 3/4
🔑 Key Tips for Success:
- Always check if fractions have the same denominator or numerator first
- Use benchmarks (especially 1/2) for quick comparisons
- On a number line, right = greater, left = smaller
- For mixed numbers, compare whole numbers before fractions
- Remember: smaller denominator = larger pieces (if numerators are equal)
- When ordering, LCD method is most accurate
📚 Fifth Grade Compare Fractions - Complete Study Guide
Master these concepts for math excellence! ✨