\(\frac{1}{2} = \frac{?}{4} = \frac{?}{6} = \frac{?}{8}\)
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 \(\frac{1}{2}\) to \(\frac{?}{4}\): denominator increased by ×2
So numerator: \(1 × 2 = 2\), giving \(\frac{2}{4}\)
From \(\frac{1}{2}\) to \(\frac{?}{6}\): denominator increased by ×3
So numerator: \(1 × 3 = 3\), giving \(\frac{3}{6}\)
From \(\frac{1}{2}\) to \(\frac{?}{8}\): denominator increased by ×4
So numerator: \(1 × 4 = 4\), giving \(\frac{4}{8}\)
\(\frac{1}{2} = \frac{2}{4}\): \(1 × 4 = 4\) and \(2 × 2 = 4\) ✓
\(\frac{1}{2} = \frac{3}{6}\): \(1 × 6 = 6\) and \(2 × 3 = 6\) ✓
\(\frac{1}{2} = \frac{4}{8}\): \(1 × 8 = 8\) and \(2 × 4 = 8\) ✓
\(\frac{1}{2} = \frac{2}{4} = \frac{3}{6} = \frac{4}{8}\)
• 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
\(\frac{3}{4} = \frac{?}{8}\), \(\frac{3}{4} = \frac{?}{12}\), \(\frac{3}{4} = \frac{?}{16}\)
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: \(8 ÷ 4 = 2\)
Numerator: \(3 × 2 = 6\), so \(\frac{6}{8}\)
Denominator multiplier: \(12 ÷ 4 = 3\)
Numerator: \(3 × 3 = 9\), so \(\frac{9}{12}\)
Denominator multiplier: \(16 ÷ 4 = 4\)
Numerator: \(3 × 4 = 12\), so \(\frac{12}{16}\)
\(\frac{3}{4} = \frac{6}{8}\): \(3 × 8 = 24\) 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 \(4 × 12 = 48\) ✓
\(\frac{3}{4} = \frac{6}{8} = \frac{9}{12} = \frac{12}{16}\)
• 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) \(\frac{2}{5}\), b) \(\frac{4}{6}\), c) \(\frac{1}{3}\)
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: \(\frac{2×2}{5×2} = \frac{4}{10}\)
×3: \(\frac{2×3}{5×3} = \frac{6}{15}\)
×4: \(\frac{2×4}{5×4} = \frac{8}{20}\)
×2: \(\frac{4×2}{6×2} = \frac{8}{12}\)
×3: \(\frac{4×3}{6×3} = \frac{12}{18}\)
×4: \(\frac{4×4}{6×4} = \frac{16}{24}\)
×2: \(\frac{1×2}{3×2} = \frac{2}{6}\)
×3: \(\frac{1×3}{3×3} = \frac{3}{9}\)
×4: \(\frac{1×4}{3×4} = \frac{4}{12}\)
\(\frac{2}{5} = \frac{4}{10}\): \(2 × 10 = 20\) and \(5 × 4 = 20\) ✓
b) \(\frac{4}{6} = \frac{8}{12} = \frac{12}{18} = \frac{16}{24}\)
c) \(\frac{1}{3} = \frac{2}{6} = \frac{3}{9} = \frac{4}{12}\)
a) \(\frac{4}{10}, \frac{6}{15}, \frac{8}{20}\)
b) \(\frac{8}{12}, \frac{12}{18}, \frac{16}{24}\)
c) \(\frac{2}{6}, \frac{3}{9}, \frac{4}{12}\)
• 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 \(\frac{18}{24}\) and \(\frac{21}{28}\):
\(18 × 28 = 504\) and \(24 × 21 = 504\)
\(\frac{18}{24} = \frac{18÷6}{24÷6} = \frac{3}{4}\)
\(\frac{21}{28} = \frac{21÷7}{28÷7} = \frac{3}{4}\)
\(\frac{18}{24} = 0.75\) and \(\frac{21}{28} = 0.75\)
All methods confirm that \(\frac{18}{24} = \frac{21}{28}\)
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 \(\frac{2}{3}\) and \(\frac{10}{15}\) to see if they are equivalent
\(2 × 15 = 30\) and \(3 × 10 = 30\)
Since both products equal 30, the fractions are equivalent
The same amount of pizza was eaten from both pizzas since \(\frac{2}{3} = \frac{10}{15}\)
\(\frac{10}{15} = \frac{10÷5}{15÷5} = \frac{2}{3}\)
The same amount of pizza was eaten from both pizzas since \(\frac{2}{3} = \frac{10}{15}\)
• 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
Complete the table showing the pattern between numerators and denominators.
Analysis: The chart shows how equivalent fractions maintain proportional relationships.
- \(\frac{1}{2} = \frac{2}{4} = \frac{3}{6} = \frac{4}{8} = \frac{5}{10}\)
- All represent 50% of the whole
- Numerator and denominator increase proportionally by the same factor