\(\frac{4}{5} = \frac{?}{10} = \frac{?}{15} = \frac{?}{20}\)
Fraction equivalents: 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 \(\frac{4}{5}\) to \(\frac{?}{10}\): denominator increased by ×2
So numerator: \(4 × 2 = 8\), giving \(\frac{8}{10}\)
From \(\frac{4}{5}\) to \(\frac{?}{15}\): denominator increased by ×3
So numerator: \(4 × 3 = 12\), giving \(\frac{12}{15}\)
From \(\frac{4}{5}\) to \(\frac{?}{20}\): denominator increased by ×4
So numerator: \(4 × 4 = 16\), giving \(\frac{16}{20}\)
\(\frac{4}{5} = \frac{8}{10}\): \(4 × 10 = 40\) and \(5 × 8 = 40\) ✓
\(\frac{4}{5} = \frac{12}{15}\): \(4 × 15 = 60\) and \(5 × 12 = 60\) ✓
\(\frac{4}{5} = \frac{16}{20}\): \(4 × 20 = 80\) and \(5 × 16 = 80\) ✓
\(\frac{4}{5} = \frac{8}{10} = \frac{12}{15} = \frac{16}{20}\)
• 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
\(\frac{7}{8} = \frac{?}{16}\), \(\frac{7}{8} = \frac{?}{24}\), \(\frac{7}{8} = \frac{?}{32}\)
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: \(16 ÷ 8 = 2\)
Numerator: \(7 × 2 = 14\), so \(\frac{14}{16}\)
Denominator multiplier: \(24 ÷ 8 = 3\)
Numerator: \(7 × 3 = 21\), so \(\frac{21}{24}\)
Denominator multiplier: \(32 ÷ 8 = 4\)
Numerator: \(7 × 4 = 28\), so \(\frac{28}{32}\)
\(\frac{7}{8} = \frac{14}{16}\): \(7 × 16 = 112\) and \(8 × 14 = 112\) ✓
\(\frac{7}{8} = \frac{21}{24}\): \(7 × 24 = 168\) and \(8 × 21 = 168\) ✓
\(\frac{7}{8} = \frac{28}{32}\): \(7 × 32 = 224\) and \(8 × 28 = 224\) ✓
\(\frac{7}{8} = \frac{14}{16} = \frac{21}{24} = \frac{28}{32}\)
• 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) \(\frac{3}{7}\), b) \(\frac{5}{9}\), c) \(\frac{2}{5}\)
Creating fraction equivalents: 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: \(\frac{3×2}{7×2} = \frac{6}{14}\)
×3: \(\frac{3×3}{7×3} = \frac{9}{21}\)
×4: \(\frac{3×4}{7×4} = \frac{12}{28}\)
×2: \(\frac{5×2}{9×2} = \frac{10}{18}\)
×3: \(\frac{5×3}{9×3} = \frac{15}{27}\)
×4: \(\frac{5×4}{9×4} = \frac{20}{36}\)
×2: \(\frac{2×2}{5×2} = \frac{4}{10}\)
×3: \(\frac{2×3}{5×3} = \frac{6}{15}\)
×4: \(\frac{2×4}{5×4} = \frac{8}{20}\)
\(\frac{3}{7} = \frac{6}{14}\): \(3 × 14 = 42\) and \(7 × 6 = 42\) ✓
b) \(\frac{5}{9} = \frac{10}{18} = \frac{15}{27} = \frac{20}{36}\)
c) \(\frac{2}{5} = \frac{4}{10} = \frac{6}{15} = \frac{8}{20}\)
a) \(\frac{6}{14}, \frac{9}{21}, \frac{12}{28}\)
b) \(\frac{10}{18}, \frac{15}{27}, \frac{20}{36}\)
c) \(\frac{4}{10}, \frac{6}{15}, \frac{8}{20}\)
• 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 \(\frac{28}{35}\) and \(\frac{32}{40}\):
\(28 × 40 = 1120\) and \(35 × 32 = 1120\)
\(\frac{28}{35} = \frac{28÷7}{35÷7} = \frac{4}{5}\)
\(\frac{32}{40} = \frac{32÷8}{40÷8} = \frac{4}{5}\)
\(\frac{28}{35} = 0.8\) and \(\frac{32}{40} = 0.8\)
All methods confirm that \(\frac{28}{35} = \frac{32}{40}\)
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 \(\frac{4}{7}\) and \(\frac{16}{28}\) to see if they are equivalent
\(4 × 28 = 112\) and \(7 × 16 = 112\)
Since both products equal 112, the fractions are equivalent
The same amount of cake was eaten from both cakes since \(\frac{4}{7} = \frac{16}{28}\)
\(\frac{16}{28} = \frac{16÷4}{28÷4} = \frac{4}{7}\)
The same amount of cake was eaten from both cakes since \(\frac{4}{7} = \frac{16}{28}\)
• 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.
- \(\frac{3}{4} = \frac{6}{8} = \frac{9}{12} = \frac{12}{16} = \frac{15}{20}\)
- All represent 75% of the whole
- Numerator and denominator increase proportionally by the same factor