Fraction: A number representing a part of a whole, written as \(\frac{\text{numerator}}{\text{denominator}}\)
Numerator: The top number showing how many parts we have
Denominator: The bottom number showing total equal parts in the whole
Proper Fraction: A fraction where the numerator is less than the denominator (\(\frac{a}{b}\) where \(a < b\))
Improper Fraction: A fraction where the numerator is greater than or equal to the denominator
Mixed Number: A number combining a whole number and a proper fraction
Equivalent Fractions: Fractions that represent the same value but use different numerators and denominators
Rational Number: Any number that can be expressed as \(\frac{p}{q}\) where p and q are integers and q ≠ 0
Rule 1: When denominators are the same, compare numerators directly
Rule 2: When numerators are the same, compare denominators inversely
Rule 3: For unlike fractions, find common denominator or use cross multiplication
Rule 4: Any fraction greater than 1 is improper; less than 1 is proper
Rule 5: Equivalent fractions have equal cross products
Rule 6: To compare mixed numbers, compare whole numbers first, then fractional parts
Rule 7: Negative fractions: compare absolute values, then apply sign rules
Rule 8: When comparing negative fractions, reverse the inequality: if \(\frac{a}{b} > \frac{c}{d}\), then \(-\frac{a}{b} < -\frac{c}{d}\)
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
Method 6 - Benchmark Comparison: Compare to known values like \(\frac{1}{2}\), \(\frac{1}{4}\), \(\frac{3}{4}\)
Method 7 - Distance from 1: For fractions close to 1, compare how far each is from 1
Method 8 - Absolute Value: For negative fractions, compare absolute values first
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 \(\frac{5}{8} > \frac{7}{12}\)
Very Complex: \(2\frac{3}{4}\) vs \(2\frac{5}{6}\) → Compare fractional parts: \(\frac{3}{4} = \frac{9}{12}\), \(\frac{5}{6} = \frac{10}{12}\), so \(2\frac{5}{6} > 2\frac{3}{4}\)
Grade 7 Advanced: \(-\frac{5}{7}\) vs \(-\frac{3}{4}\) → Compare absolute values: \(\frac{5}{7}\) vs \(\frac{3}{4}\) → \(\frac{5}{7} < \frac{3}{4}\), so \(-\frac{5}{7} > -\frac{3}{4}\)
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
Tip 4: For mixed numbers, convert to improper fractions if easier to compare
Tip 5: Use prime factorization to efficiently find LCD for complex denominators
Tip 6: For negative fractions, compare absolute values first, then reverse the inequality
Pitfall 1: Don't just compare numerators without considering denominators
Pitfall 2: Forgetting that \(\frac{4}{4} = 1\) and \(\frac{5}{4} > 1\)
Pitfall 3: Not simplifying fractions before comparing
Pitfall 4: Confusing negative fraction comparisons
Pitfall 5: Forgetting to reverse inequality for negative fractions
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
Shortcut: If one fraction is clearly greater than 1 and the other is less than 1, the comparison is obvious
Advanced Shortcut: For fractions close to 1, compare their distances from 1
Negative Rule: The larger the absolute value of a negative number, the smaller the number itself
Cross Multiplication: For \(\frac{a}{b}\) vs \(\frac{c}{d}\), compare \(a \times d\) vs \(b \times c\). If \(a \times d > b \times c\), then \(\frac{a}{b} > \frac{c}{d}\).
Visual Model:
\(\frac{3}{4}\) vs \(\frac{5}{6}\)
- Cross multiply: \(3 \times 6 = 18\) vs \(4 \times 5 = 20\)
- Compare results: 18 vs 20
- Since 20 > 18, then \(\frac{5}{6} > \frac{3}{4}\)
\(3 \times 6 = 18\) and \(4 \times 5 = 20\)
18 vs 20 → 20 is greater than 18
Since \(4 \times 5 > 3 \times 6\), then \(\frac{5}{6} > \frac{3}{4}\)
Decimal Verification: \(\frac{3}{4} = 0.75\) and \(\frac{5}{6} ≈ 0.833\), confirming \(0.833 > 0.75\)
\(\frac{5}{6}\) is greater than \(\frac{3}{4}\)
• Cross Multiplication: Multiply diagonally and compare products
• Comparison: Larger product indicates larger fraction
• Verification: Convert to decimals to confirm
Mixed Numbers: Compare whole numbers first. If equal, compare fractional parts using fraction comparison rules.
Visual Model:
vs\(2\frac{3}{5}\) vs \(2\frac{4}{7}\)
- Compare whole numbers: 2 vs 2 → Equal
- Compare fractional parts: \(\frac{3}{5}\) vs \(\frac{4}{7}\)
- Cross multiply: \(3 \times 7 = 21\) vs \(5 \times 4 = 20\)
- Since 21 > 20, then \(\frac{3}{5} > \frac{4}{7}\)
Both have whole number 2, so they are equal
Now compare \(\frac{3}{5}\) vs \(\frac{4}{7}\)
\(3 \times 7 = 21\) and \(5 \times 4 = 20\)
21 vs 20 → 21 is greater than 20
Since \(\frac{3}{5} > \frac{4}{7}\), then \(2\frac{3}{5} > 2\frac{4}{7}\)
Decimal Verification: \(2\frac{3}{5} = 2.6\) and \(2\frac{4}{7} ≈ 2.571\), confirming \(2.6 > 2.571\)
\(2\frac{3}{5}\) is greater than \(2\frac{4}{7}\)
• Mixed Number Comparison: Whole numbers first, then fractions
• Cross Multiplication: Compare fractional parts when whole numbers are equal
• Verification: Convert to decimals to confirm result
Equivalent Fractions: Two fractions are equivalent if their cross products are equal.
Visual Model:
=\(\frac{12}{18}\) vs \(\frac{8}{12}\) (both equal \(\frac{2}{3}\))
- Cross multiply: \(12 \times 12 = 144\) vs \(18 \times 8 = 144\)
- Compare results: 144 vs 144
- Since 144 = 144, then \(\frac{12}{18} = \frac{8}{12}\)
\(12 \times 12 = 144\) and \(18 \times 8 = 144\)
144 vs 144 → Products are equal
\(\frac{12}{18} = \frac{12 ÷ 6}{18 ÷ 6} = \frac{2}{3}\)
\(\frac{8}{12} = \frac{8 ÷ 4}{12 ÷ 4} = \frac{2}{3}\)
Since both fractions simplify to \(\frac{2}{3}\), they are equivalent
Decimal Verification: \(\frac{12}{18} = 0.667\) and \(\frac{8}{12} = 0.667\), confirming they are equivalent
Yes, \(\frac{12}{18}\) and \(\frac{8}{12}\) 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 = 12
- Convert each fraction to have denominator 12
- Compare numerators of converted fractions
- Order by increasing numerator values
LCD of 2, 3, 4, 6 is 12
\(\frac{1}{2} = \frac{6}{12}\), \(\frac{2}{3} = \frac{8}{12}\), \(\frac{3}{4} = \frac{9}{12}\), \(\frac{5}{6} = \frac{10}{12}\)
6, 8, 9, 10 → Order from least to greatest: 6, 8, 9, 10
\(\frac{6}{12} < \frac{8}{12} < \frac{9}{12} < \frac{10}{12}\)
\(\frac{1}{2} < \frac{2}{3} < \frac{3}{4} < \frac{5}{6}\)
Decimal Verification: 0.5, 0.667, 0.75, 0.833, confirming the order
From least to greatest: \(\frac{1}{2}, \frac{2}{3}, \frac{3}{4}, \frac{5}{6}\)
• Common Denominator: Convert all fractions to same denominator
• Ordering: Compare numerators once denominators are equal
• Verification: Convert to decimals to confirm order
Negative Fractions: Compare absolute values first, then reverse the inequality. The larger absolute value corresponds to the smaller negative number.
Number Line Model:
- Compare absolute values: \(\frac{3}{5}\) vs \(\frac{2}{3}\)
- Cross multiply: \(3 \times 3 = 9\) vs \(5 \times 2 = 10\)
- Since \(9 < 10\), then \(\frac{3}{5} < \frac{2}{3}\)
- Reverse the inequality for negatives: \(-\frac{3}{5} > -\frac{2}{3}\)
Compare \(\left|-\frac{3}{5}\right| = \frac{3}{5}\) vs \(\left|-\frac{2}{3}\right| = \frac{2}{3}\)
\(3 \times 3 = 9\) and \(5 \times 2 = 10\)
9 vs 10 → 9 is less than 10
Since \(9 < 10\), then \(\frac{3}{5} < \frac{2}{3}\)
For negative numbers, if \(\frac{3}{5} < \frac{2}{3}\), then \(-\frac{3}{5} > -\frac{2}{3}\)
Decimal Verification: \(-\frac{3}{5} = -0.6\) and \(-\frac{2}{3} ≈ -0.667\), confirming \(-0.6 > -0.667\)
\(-\frac{3}{5}\) is greater than \(-\frac{2}{3}\)
• Negative Fraction Rule: Compare absolute values first, then reverse inequality
• Cross Multiplication: Compare absolute values using standard method
• Verification: Convert to decimals to confirm result