Is 2/3 Bigger Than 5/8?

Method 1: Common Denominators

To compare these fractions, we need a common denominator. The denominators are 3 and 8, and the least common denominator (LCD) is 24.

• Step 1. Convert \(\frac{2}{3}\): multiply numerator and denominator by 8.
  \[\frac{2}{3} = \frac{2 \times 8}{3 \times 8} = \frac{16}{24}\]
• Step 2. Convert \(\frac{5}{8}\): multiply numerator and denominator by 3.
  \[\frac{5}{8} = \frac{5 \times 3}{8 \times 3} = \frac{15}{24}\]
• Step 3. Compare the numerators: 16 vs 15.
• Step 4. Since 16 is greater than 15, we know that \(\frac{2}{3} > \frac{5}{8}\).

Method 2: Cross Multiplication

A quicker way to compare fractions is to cross-multiply. Multiply each numerator by the other fraction's denominator:

• Step 1. Multiply the numerator of the first fraction by the denominator of the second: \(2 \times 8 = 16\).
• Step 2. Multiply the numerator of the second fraction by the denominator of the first: \(5 \times 3 = 15\).
• Step 3. Compare the products: \(16 > 15\), so \(\frac{2}{3} > \frac{5}{8}\).

Method 3: Decimal Comparison

Convert each fraction to a decimal by dividing the numerator by the denominator:

Since 0.666667 is greater than 0.625, we confirm that \(\frac{2}{3} > \frac{5}{8}\). In percentage terms, \(\frac{2}{3}\) is 66.6667% and \(\frac{5}{8}\) is 62.5%, a difference of 4.1667 percentage points.

Why Does This Work?

These fractions have different numerators and different denominators, so we can't compare them directly. By converting to a common denominator of 24, we're cutting both quantities into equal-sized pieces. Then 16 pieces vs 15 pieces is a straightforward comparison.