Fraction: A number representing a part of a whole, written as numerator/denominator
Numerator: The top number showing how many parts we have
Denominator: The bottom number showing total equal parts in the whole
Equivalent Fractions: Fractions that represent the same value but use different numbers
Improper Fraction: A fraction where the numerator is greater than or equal to the denominator
Mixed Number: A combination of a whole number and a proper fraction
Rule 1: When denominators are the same, compare numerators (larger numerator = larger fraction)
Rule 2: When numerators are the same, compare denominators (smaller denominator = larger fraction)
Rule 3: When both are different, use cross multiplication or find common denominators
Rule 4: Any fraction greater than 1 is an improper fraction; less than 1 is proper
Rule 5: Equivalent fractions have equal cross products
Method 1 - Same Denominator: Compare numerators directly
Method 2 - Same Numerator: Compare denominators (inverse relationship)
Method 3 - Cross Multiplication: Multiply diagonally and compare products
Method 4 - Common Denominator: Convert to same denominator, then compare numerators
Method 5 - Decimal Conversion: Convert fractions to decimals and compare
Simple: \(\frac{3}{5}\) vs \(\frac{2}{5}\) → Same denominator, 3 > 2, so \(\frac{3}{5} > \frac{2}{5}\)
Moderate: \(\frac{2}{3}\) vs \(\frac{2}{5}\) → Same numerator, 3 < 5, so \(\frac{2}{3} > \frac{2}{5}\)
Advanced: \(\frac{3}{4}\) vs \(\frac{5}{6}\) → Cross multiply: \(3 \times 6 = 18\), \(4 \times 5 = 20\), so \(\frac{5}{6} > \frac{3}{4}\)
Complex: \(\frac{7}{12}\) vs \(\frac{5}{8}\) → LCD = 24: \(\frac{14}{24}\) vs \(\frac{15}{24}\), so \(\frac{5}{8} > \frac{7}{12}\)
Tip 1: Always identify whether denominators or numerators are the same first
Tip 2: Remember: larger denominator = smaller fraction (when numerators are equal)
Tip 3: Use benchmarks like \(\frac{1}{2}\), \(\frac{1}{4}\), \(\frac{3}{4}\) to estimate
Pitfall 1: Don't just compare numerators without considering denominators
Pitfall 2: Forgetting that \(\frac{4}{4} = 1\) and \(\frac{5}{4} > 1\)
Memory Aid: "More pieces, smaller pieces" - when denominator increases, each piece gets smaller
Formula: For \(\frac{a}{b}\) vs \(\frac{c}{d}\): if \(a \times d > b \times c\), then \(\frac{a}{b} > \frac{c}{d}\)
Pattern: Fractions increase as they approach 1 (from below) or decrease as they move away from 1
Verification: Always check your answer by converting to decimals or drawing models
Mixed Numbers: Compare whole numbers first. If equal, compare fractional parts using fraction comparison rules.
Visual Model:
\(1\frac{2}{3}\) vs \(1\frac{3}{4}\)
- Compare whole numbers: 1 vs 1 → Equal
- Compare fractional parts: \(\frac{2}{3}\) vs \(\frac{3}{4}\)
- Use cross multiplication: \(2 \times 4 = 8\) vs \(3 \times 3 = 9\)
- Since 9 > 8, then \(\frac{3}{4} > \frac{2}{3}\)
Both have whole number 1, so they are equal
Now compare \(\frac{2}{3}\) vs \(\frac{3}{4}\)
\(2 \times 4 = 8\) and \(3 \times 3 = 9\)
8 vs 9 → 9 is greater than 8
Since \(\frac{3}{4} > \frac{2}{3}\), then \(1\frac{3}{4} > 1\frac{2}{3}\)
\(1\frac{3}{4}\) is greater than \(1\frac{2}{3}\)
• Mixed Number Comparison: Whole numbers first, then fractions
• Cross Multiplication: Compare fractional parts when whole numbers are equal
• Conversion: Can convert to improper fractions if needed
Improper Fractions: Use same comparison methods as proper fractions. Both are greater than 1.
Visual Model:
\(\frac{7}{4}\) vs \(\frac{9}{5}\)
- Use cross multiplication: \(7 \times 5 = 35\) vs \(4 \times 9 = 36\)
- Compare results: 35 vs 36
- Since 36 > 35, then \(\frac{9}{5} > \frac{7}{4}\)
\(7 \times 5 = 35\) and \(4 \times 9 = 36\)
35 vs 36 → 36 is greater than 35
Since \(4 \times 9 > 7 \times 5\), then \(\frac{9}{5} > \frac{7}{4}\)
\(\frac{7}{4} = 1.75\) and \(\frac{9}{5} = 1.8\), confirming \(1.8 > 1.75\)
\(\frac{9}{5}\) is greater than \(\frac{7}{4}\)
• Improper Fraction Rule: Same comparison methods apply
• Cross Multiplication: Works for any fractions
• Decimal Verification: Convert to decimals to confirm
Complex Fractions: Use LCD method or cross multiplication for accurate comparison.
Visual Model:
vs\(\frac{11}{12}\) vs \(\frac{7}{8}\)
- Find LCD of 12 and 8 = 24
- Convert: \(\frac{11}{12} = \frac{22}{24}\) and \(\frac{7}{8} = \frac{21}{24}\)
- Compare numerators: 22 vs 21
- Since 22 > 21, then \(\frac{22}{24} > \frac{21}{24}\)
LCD of 12 and 8 is 24 (smallest number divisible by both)
\(\frac{11}{12} = \frac{11 \times 2}{12 \times 2} = \frac{22}{24}\)
\(\frac{7}{8} = \frac{7 \times 3}{8 \times 3} = \frac{21}{24}\)
22 vs 21 → 22 is greater than 21
Since denominators are the same, larger numerator means larger fraction
Cross multiply: \(11 \times 8 = 88\) vs \(12 \times 7 = 84\), confirming \(88 > 84\)
\(\frac{11}{12}\) is greater than \(\frac{7}{8}\)
• Common Denominator: Convert to same denominator for direct comparison
• Equivalent Fractions: Maintain value while changing representation
• Alternative Method: Cross multiplication provides verification
Equivalent Fractions: Two fractions are equivalent if their cross products are equal.
Visual Model:
=\(\frac{15}{20}\) vs \(\frac{9}{12}\) (both equal \(\frac{3}{4}\))
- Method 1: Cross multiply: \(15 \times 12 = 180\) vs \(20 \times 9 = 180\)
- Method 2: Simplify both fractions to lowest terms
- \(\frac{15}{20} = \frac{3}{4}\) and \(\frac{9}{12} = \frac{3}{4}\)
\(15 \times 12 = 180\) and \(20 \times 9 = 180\)
180 vs 180 → Products are equal
GCD of 15 and 20 is 5: \(\frac{15 \div 5}{20 \div 5} = \frac{3}{4}\)
GCD of 9 and 12 is 3: \(\frac{9 \div 3}{12 \div 3} = \frac{3}{4}\)
Both fractions simplify to \(\frac{3}{4}\), so they are equivalent
Yes, \(\frac{15}{20}\) and \(\frac{9}{12}\) are equivalent fractions
• Equivalence Test: Cross products must be equal
• Simplification: Reduce to lowest terms using GCD
• Verification: Both methods confirm equivalence
Ordering Fractions: Find a common denominator and compare numerators, or convert to decimals.
Number Line:
- Find LCD of denominators 2, 3, 4, 6, 8 = 24
- Convert each fraction to have denominator 24
- Compare numerators of converted fractions
- Order by increasing numerator values
LCD of 2, 3, 4, 6, 8 is 24
\(\frac{1}{2} = \frac{12}{24}\), \(\frac{2}{3} = \frac{16}{24}\), \(\frac{3}{4} = \frac{18}{24}\), \(\frac{5}{6} = \frac{20}{24}\), \(\frac{7}{8} = \frac{21}{24}\)
12, 16, 18, 20, 21 → Order from least to greatest: 12, 16, 18, 20, 21
\(\frac{12}{24} < \frac{16}{24} < \frac{18}{24} < \frac{20}{24} < \frac{21}{24}\)
\(\frac{1}{2} < \frac{2}{3} < \frac{3}{4} < \frac{5}{6} < \frac{7}{8}\)
From least to greatest: \(\frac{1}{2}, \frac{2}{3}, \frac{3}{4}, \frac{5}{6}, \frac{7}{8}\)
• Common Denominator: Convert all fractions to same denominator
• Ordering: Compare numerators once denominators are equal
• Verification: Convert to decimals to confirm order