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Fractions - Equivalent Fractions

Grade 4ICSE

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

๐Ÿ”‘Concepts

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Definition of Equivalent Fractions: Equivalent fractions are fractions that represent the same part of a whole or the same value, even though they have different numerators and denominators. Visually, if you have two identical circles, shading 12\frac{1}{2} of the first circle covers the same area as shading 24\frac{2}{4} or 48\frac{4}{8} of the second circle.

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Finding Equivalents by Multiplication: You can create an equivalent fraction by multiplying both the numerator and the denominator by the same non-zero number. For example, to find a fraction equivalent to 13\frac{1}{3}, you can multiply both top and bottom by 22 to get 26\frac{2}{6}. This is like taking a chocolate bar divided into 33 large pieces and cutting each piece into 22 smaller pieces to get 66 total pieces.

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Finding Equivalents by Division: If both the numerator and denominator have a common factor, you can divide them by that same number to get an equivalent fraction. This process is often called simplifying or reducing. For instance, 1020\frac{10}{20} can be divided by 1010 on both sides to get 12\frac{1}{2}, showing that 1010 out of 2020 items is the same as half the items.

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The Property of One: Any fraction where the numerator and denominator are the same, such as 22\frac{2}{2}, 55\frac{5}{5}, or 100100\frac{100}{100}, is equal to 11. Multiplying a fraction by nn\frac{n}{n} does not change its value, only its appearance, which is why the resulting fraction is equivalent.

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Equivalent Fractions on a Number Line: On a number line marked from 00 to 11, equivalent fractions occupy the exact same point. For example, if you divide the line into 44 parts, the second mark is 24\frac{2}{4}. If you divide the same line into 22 parts, the first mark is 12\frac{1}{2}. Both marks sit at the exact center of the line.

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Checking Equivalence using Cross-Multiplication: 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 (aร—da \times d) and the denominator of the first by the numerator of the second (bร—cb \times c). If the two products are equal, the fractions are equivalent.

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Simplest Form: A fraction is in its simplest form when the only common factor between the numerator and the denominator is 11. For example, 34\frac{3}{4} is in simplest form because no number other than 11 can divide both 33 and 44 exactly.

๐Ÿ“Formulae

ab=aร—nbร—n\frac{a}{b} = \frac{a \times n}{b \times n} (where nโ‰ 0n \neq 0)

ab=aรทnbรทn\frac{a}{b} = \frac{a \div n}{b \div n} (where nn is a common factor)

ab=cd\frac{a}{b} = \frac{c}{d} if and only if aร—d=bร—ca \times d = b \times c

๐Ÿ’กExamples

Problem 1:

Find an equivalent fraction of 35\frac{3}{5} with a denominator of 2020.

Solution:

Step 1: Identify what number the original denominator 55 must be multiplied by to get the new denominator 2020. 20รท5=420 \div 5 = 4 Step 2: Multiply both the numerator and the denominator of 35\frac{3}{5} by 44. 3ร—45ร—4=1220\frac{3 \times 4}{5 \times 4} = \frac{12}{20} Answer: 1220\frac{12}{20}

Explanation:

To keep the fraction equivalent, we must perform the same multiplication operation on both the top and the bottom parts of the fraction.

Problem 2:

Check if 26\frac{2}{6} and 412\frac{4}{12} are equivalent fractions using cross-multiplication.

Solution:

Step 1: Multiply the numerator of the first fraction by the denominator of the second fraction: 2ร—12=242 \times 12 = 24 Step 2: Multiply the denominator of the first fraction by the numerator of the second fraction: 6ร—4=246 \times 4 = 24 Step 3: Compare the products. Since 24=2424 = 24, the fractions are equivalent.

Explanation:

Cross-multiplication is a quick way to verify equivalence. If the products of the diagonal numbers are equal, the fractions represent the same value.