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Fractions and Decimals - Equivalent Fractions

Grade 4IB

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

🔑Concepts

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.

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.

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.

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.

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.

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.

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.