\(\frac{3}{4} = \frac{?}{8} = \frac{?}{12} = \frac{?}{16}\)
Equivalent fractions: Fractions that represent the same value or proportion of a whole, even though they may have different numerators and denominators.
Key principle: The value of a fraction remains unchanged when both numerator and denominator are multiplied or divided by the same non-zero number.
- Identify the relationship: Look at the denominators to find the multiplier
- Apply the multiplier: Multiply both numerator and denominator by the same number
- Verify: Use cross-multiplication to confirm equivalence
From \(\frac{3}{4}\) to \(\frac{?}{8}\): denominator increased by ×2
So numerator: \(3 × 2 = 6\), giving \(\frac{6}{8}\)
From \(\frac{3}{4}\) to \(\frac{?}{12}\): denominator increased by ×3
So numerator: \(3 × 3 = 9\), giving \(\frac{9}{12}\)
From \(\frac{3}{4}\) to \(\frac{?}{16}\): denominator increased by ×4
So numerator: \(3 × 4 = 12\), giving \(\frac{12}{16}\)
\(\frac{3}{4} = \frac{6}{8}\): \(3 × 8 = 24\) and \(4 × 6 = 24\) ✓
\(\frac{3}{4} = \frac{9}{12}\): \(3 × 12 = 36\) and \(4 × 9 = 36\) ✓
\(\frac{3}{4} = \frac{12}{16}\): \(3 × 16 = 48\) and \(4 × 12 = 48\) ✓
\(\frac{3}{4} = \frac{6}{8} = \frac{9}{12} = \frac{12}{16}\)
• Equivalent fraction rule: \(\frac{a}{b} = \frac{a×n}{b×n}\) where \(n ≠ 0\)
• Cross-multiplication test: If \(a/b = c/d\), then \(a × d = b × c\)
• Conservation principle: Value remains unchanged when multiplying by 1
\(\frac{5}{6} = \frac{?}{12}\), \(\frac{5}{6} = \frac{?}{18}\), \(\frac{5}{6} = \frac{?}{24}\)
Finding missing numerators: When the denominator is given and the numerator is unknown, determine the multiplier and apply it to the known numerator.
Proportional reasoning: Maintaining the same ratio between numerator and denominator.
Denominator multiplier: \(12 ÷ 6 = 2\)
Numerator: \(5 × 2 = 10\), so \(\frac{10}{12}\)
Denominator multiplier: \(18 ÷ 6 = 3\)
Numerator: \(5 × 3 = 15\), so \(\frac{15}{18}\)
Denominator multiplier: \(24 ÷ 6 = 4\)
Numerator: \(5 × 4 = 20\), so \(\frac{20}{24}\)
\(\frac{5}{6} = \frac{10}{12}\): \(5 × 12 = 60\) and \(6 × 10 = 60\) ✓
\(\frac{5}{6} = \frac{15}{18}\): \(5 × 18 = 90\) and \(6 × 15 = 90\) ✓
\(\frac{5}{6} = \frac{20}{24}\): \(5 × 24 = 120\) and \(6 × 20 = 120\) ✓
\(\frac{5}{6} = \frac{10}{12} = \frac{15}{18} = \frac{20}{24}\)
• Proportional scaling: Whatever you do to the denominator, do to the numerator
• Cross-multiplication test: If \(a/b = c/d\), then \(a × d = b × c\)
• Conservation principle: Value remains unchanged when multiplying by 1
a) \(\frac{2}{7}\), b) \(\frac{4}{9}\), c) \(\frac{3}{5}\)
Creating equivalent fractions: Starting with one fraction and generating multiple equivalent forms by multiplying by different whole numbers.
Pattern recognition: Each equivalent fraction maintains the same proportional relationship.
×2: \(\frac{2×2}{7×2} = \frac{4}{14}\)
×3: \(\frac{2×3}{7×3} = \frac{6}{21}\)
×4: \(\frac{2×4}{7×4} = \frac{8}{28}\)
×2: \(\frac{4×2}{9×2} = \frac{8}{18}\)
×3: \(\frac{4×3}{9×3} = \frac{12}{27}\)
×4: \(\frac{4×4}{9×4} = \frac{16}{36}\)
×2: \(\frac{3×2}{5×2} = \frac{6}{10}\)
×3: \(\frac{3×3}{5×3} = \frac{9}{15}\)
×4: \(\frac{3×4}{5×4} = \frac{12}{20}\)
\(\frac{2}{7} = \frac{4}{14}\): \(2 × 14 = 28\) and \(7 × 4 = 28\) ✓
b) \(\frac{4}{9} = \frac{8}{18} = \frac{12}{27} = \frac{16}{36}\)
c) \(\frac{3}{5} = \frac{6}{10} = \frac{9}{15} = \frac{12}{20}\)
a) \(\frac{4}{14}, \frac{6}{21}, \frac{8}{28}\)
b) \(\frac{8}{18}, \frac{12}{27}, \frac{16}{36}\)
c) \(\frac{6}{10}, \frac{9}{15}, \frac{12}{20}\)
• Equivalent fraction rule: \(\frac{a}{b} = \frac{a×n}{b×n}\) where \(n ≠ 0\)
• Infinitely many equivalents: Any whole number multiplier works
• Verification: Cross-multiplication confirms equivalence
Numerator: The top number in a fraction (represents the number of parts taken)
Denominator: The bottom number in a fraction (represents the total number of equal parts)
Equivalent fractions: Fractions that represent the same value or proportion
Cross-multiplication: Multiplying diagonally across an equation of fractions
- Identify parts: Determine known numerator, denominator, and unknown value
- Find multiplier: Determine what number was used to scale the known part
- Apply multiplier: Multiply or divide both parts by the same number
- Verify: Use cross-multiplication to confirm equivalence
• Equivalent fraction rule: \(\frac{a}{b} = \frac{a×n}{b×n}\) where \(n ≠ 0\)
• Cross-multiplication test: \(\frac{a}{b} = \frac{c}{d}\) if \(a×d = b×c\)
• Both numerator and denominator must be multiplied/divided by the same number
• The value of the fraction remains unchanged
Advanced equivalence testing: Using multiple verification methods to determine if two fractions are equivalent.
Simplification method: Reducing both fractions to lowest terms to compare.
For \(\frac{24}{36}\) and \(\frac{30}{45}\):
\(24 × 45 = 1080\) and \(36 × 30 = 1080\)
\(\frac{24}{36} = \frac{24÷12}{36÷12} = \frac{2}{3}\)
\(\frac{30}{45} = \frac{30÷15}{45÷15} = \frac{2}{3}\)
\(\frac{24}{36} = 0.666...\) and \(\frac{30}{45} = 0.666...\)
All methods confirm that \(\frac{24}{36} = \frac{30}{45}\)
Three methods confirm equivalence: cross-multiplication, simplification, decimal conversion
• Cross-multiplication test: If \(a/b = c/d\), then \(a × d = b × c\)
• Simplification method: Reduce both fractions to lowest terms
• Transitive property: If both equal the same reduced fraction, they are equivalent
Word problems: Real-life situations that require comparing fractions.
Proportional comparison: Determining if different representations mean the same amount.
Compare \(\frac{5}{8}\) and \(\frac{20}{32}\) to see if they are equivalent
\(5 × 32 = 160\) and \(8 × 20 = 160\)
Since both products equal 160, the fractions are equivalent
Sarah and Tom ate the same amount of chocolate since \(\frac{5}{8} = \frac{20}{32}\)
\(\frac{20}{32} = \frac{20÷4}{32÷4} = \frac{5}{8}\)
Sarah and Tom ate the same amount of chocolate since \(\frac{5}{8} = \frac{20}{32}\)
• Cross-multiplication test: If \(a/b = c/d\), then \(a × d = b × c\)
• Equivalence principle: Equivalent fractions represent the same amount
• Context interpretation: Equivalent fractions mean equal portions
Fraction: A number representing a part of a whole, expressed as \(\frac{numerator}{denominator}\)
Equivalent fractions: Different fractions that represent the same value or proportion
Proportion: A relationship between quantities showing that they are equivalent
- Identify the given fraction and target: Know what you're looking for
- Determine the scaling factor: Find what number to multiply or divide by
- Apply the operation: Multiply or divide both numerator and denominator
- Verify equivalence: Use cross-multiplication to confirm
• Equivalent fraction formula: \(\frac{a}{b} = \frac{a×n}{b×n}\) where \(n ≠ 0\)
• Cross-multiplication test: \(\frac{a}{b} = \frac{c}{d}\) if \(a×d = b×c\)
• Simplification rule: \(\frac{a}{b} = \frac{a÷n}{b÷n}\) if \(n\) divides both
• Both parts must be changed by the same factor to maintain equivalence
Notice the consistent relationship between numerators and denominators.
Analysis: The chart shows how equivalent fractions maintain proportional relationships.
- \(\frac{2}{3} = \frac{4}{6} = \frac{6}{9} = \frac{8}{12} = \frac{10}{15}\)
- All represent approximately 66.67% of the whole
- Numerator and denominator increase proportionally by the same factor