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Fractions - Equivalent Fractions

Grade 6CBSE

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

Understanding Equivalence: Equivalent fractions are different fractions that represent the same part of a whole. Visually, if you have two identical rectangular cakes, and you cut one into 2 equal parts and take 1 (12\frac{1}{2}), and cut the other into 4 equal parts and take 2 (24\frac{2}{4}), you have the same amount of cake in both cases.

Finding Equivalents by Multiplication: To find an equivalent fraction, you can multiply both the numerator and the denominator by the same non-zero whole number. This is like taking the same area and dividing it into even smaller, equal-sized pieces without changing the total shaded amount.

Finding Equivalents by Division: You can also find an equivalent fraction by dividing both the numerator and the denominator by a common factor. This process, often called simplification, reduces the number of parts while keeping the total value the same.

Simplest Form (Lowest Terms): A fraction is said to be in its simplest form if its numerator and denominator have no common factor other than 1. Visually, this represents the fraction using the fewest possible number of parts to describe the same whole.

The Cross-Multiplication Rule: To check if two fractions ab\frac{a}{b} and cd\frac{c}{d} are equivalent, you can multiply the numerator of the first by the denominator of the second (a×da \times d) and the denominator of the first by the numerator of the second (b×cb \times c). If the products are equal, the fractions are equivalent.

Number Line Representation: Equivalent fractions occupy the exact same spot on a number line. For example, if you draw a number line from 0 to 1, the point exactly in the middle represents 12\frac{1}{2}, 24\frac{2}{4}, 36\frac{3}{6}, and 50100\frac{50}{100} all at once.

Property of 1: Multiplying a fraction by nn\frac{n}{n} (where n0n \neq 0) is the same as multiplying by 1. Since any number multiplied by 1 remains the same, the value of the fraction does not change, even though its 'appearance' does.

📐Formulae

ab=a×nb×n (where n0)\frac{a}{b} = \frac{a \times n}{b \times n} \text{ (where } n \neq 0)

ab=a÷nb÷n (where n is a common factor)\frac{a}{b} = \frac{a \div n}{b \div n} \text{ (where } n \text{ is a common factor)}

ab=cd    a×d=b×c\frac{a}{b} = \frac{c}{d} \iff a \times d = b \times c

Simplest Form: HCF(numerator, denominator)=1\text{Simplest Form: } \text{HCF}(\text{numerator, denominator}) = 1

💡Examples

Problem 1:

Find an equivalent fraction of 34\frac{3}{4} with the denominator 20.

Solution:

  1. Identify the relationship between the denominators: 20÷4=520 \div 4 = 5.
  2. To keep the fraction equivalent, multiply both the numerator and the denominator by 5: 3×54×5=1520\frac{3 \times 5}{4 \times 5} = \frac{15}{20}
  3. The equivalent fraction is 1520\frac{15}{20}.

Explanation:

To find an equivalent fraction with a specific denominator, we determine what factor the original denominator was multiplied by to get the new one, and apply that same factor to the numerator.

Problem 2:

Reduce the fraction 1824\frac{18}{24} to its simplest form.

Solution:

  1. Find the Highest Common Factor (HCF) of 18 and 24. The factors of 18 are 1, 2, 3, 6, 9, 18. The factors of 24 are 1, 2, 3, 4, 6, 8, 12, 24. The HCF is 6.
  2. Divide both the numerator and denominator by the HCF: 18÷624÷6=34\frac{18 \div 6}{24 \div 6} = \frac{3}{4}
  3. Since 3 and 4 have no common factors other than 1, 34\frac{3}{4} is the simplest form.

Explanation:

Dividing both terms of a fraction by their Greatest Common Divisor (or HCF) reduces the fraction to its lowest terms in a single step.

Problem 3:

Check whether 59\frac{5}{9} and 3054\frac{30}{54} are equivalent.

Solution:

  1. Use the cross-multiplication method: Multiply 5×545 \times 54 and 9×309 \times 30.
  2. 5×54=2705 \times 54 = 270.
  3. 9×30=2709 \times 30 = 270.
  4. Since 270=270270 = 270, the cross-products are equal.

Explanation:

If the product of the first numerator and second denominator equals the product of the first denominator and second numerator, the two fractions represent the same value.