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Fractions and Decimals - Equivalent Fractions

Grade 4IB

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

🔑Concepts

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Equivalent fractions are fractions that represent the same value or the same part of a whole, even though they have different numerators and denominators. Imagine two identical circles: if you shade 12\frac{1}{2} of the first circle and 24\frac{2}{4} of the second circle, you will see that the exact same amount of space is covered in both.

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To find an equivalent fraction, you can multiply both the numerator and the denominator by the same non-zero number. For instance, 23×22=46\frac{2}{3} \times \frac{2}{2} = \frac{4}{6}. Visually, this is like taking a rectangle divided into 3 vertical strips and drawing a horizontal line across the middle to double the total number of pieces.

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Simplification is the process of finding an equivalent fraction with smaller numbers by dividing both the numerator and the denominator by their greatest common factor. If you have 612\frac{6}{12} and divide both parts by 66, you get 12\frac{1}{2}. This looks like removing grid lines in a drawing to group smaller sections into fewer, larger ones.

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The Identity Property of Multiplication states that any number multiplied by 11 stays the same. In fractions, 11 can be written as 22\frac{2}{2}, 55\frac{5}{5}, or 100100\frac{100}{100}. Multiplying a fraction by these forms of 11 changes the numbers but keeps the fraction's value equivalent.

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A fraction wall is a visual tool used to compare fractions. It consists of stacked rows where the top row is a whole block (11) and lower rows are divided into halves, thirds, fourths, etc. By looking straight down a vertical line on the wall, you can see that the edge of the 13\frac{1}{3} block aligns perfectly with the edge of the 26\frac{2}{6} block, showing they are equivalent.

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On a number line, equivalent fractions occupy the exact same position. If you draw a number line from 00 to 11 and mark the point for 34\frac{3}{4}, that same physical spot represents 68\frac{6}{8} if you were to divide the line into eight equal segments instead of four.

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You can test if two fractions are equivalent using cross-multiplication. For the fractions ab\frac{a}{b} and cd\frac{c}{d}, they are equivalent if the product of the first numerator and second denominator (a×da \times d) equals the product of the first denominator and second numerator (b×cb \times c).

📐Formulae

ab=a×nb×n\frac{a}{b} = \frac{a \times n}{b \times n}

ab=a÷nb÷n\frac{a}{b} = \frac{a \div n}{b \div n}

nn=1\frac{n}{n} = 1

ab=cd if and only if a×d=b×c\frac{a}{b} = \frac{c}{d} \text{ if and only if } a \times d = b \times c

💡Examples

Problem 1:

Find an equivalent fraction for 34\frac{3}{4} that has a denominator of 1212.

Solution:

Step 1: Determine what number the current denominator (44) must be multiplied by to get the new denominator (1212). 12÷4=312 \div 4 = 3 Step 2: Multiply both the numerator and the denominator of the original fraction by 33. 3×34×3=912\frac{3 \times 3}{4 \times 3} = \frac{9}{12} Final Answer: 912\frac{9}{12}

Explanation:

To keep the fraction equivalent, we must perform the same multiplication operation on both the top and the bottom numbers. Since the denominator tripled, the numerator must also triple.

Problem 2:

Simplify the fraction 1015\frac{10}{15} to its lowest terms.

Solution:

Step 1: Identify a common factor for both 1010 and 1515. Both numbers end in 00 or 55, so they are divisible by 55. Step 2: Divide the numerator by 55. 10÷5=210 \div 5 = 2 Step 3: Divide the denominator by 55. 15÷5=315 \div 5 = 3 Resulting fraction: 23\frac{2}{3}. Since 22 and 33 have no common factors other than 11, it is in simplest form. Final Answer: 23\frac{2}{3}

Explanation:

Simplification is finding an equivalent fraction by dividing. By dividing both parts by the greatest common factor, we reach the simplest version of the fraction.