Is 5/8 Bigger Than 8/9?

Method 1: Common Denominators

To compare these fractions, we need a common denominator. The denominators are 8 and 9, and the least common denominator (LCD) is 72.

• Step 1. Convert \(\frac{5}{8}\): multiply numerator and denominator by 9.
  \[\frac{5}{8} = \frac{5 \times 9}{8 \times 9} = \frac{45}{72}\]
• Step 2. Convert \(\frac{8}{9}\): multiply numerator and denominator by 8.
  \[\frac{8}{9} = \frac{8 \times 8}{9 \times 8} = \frac{64}{72}\]
• Step 3. Compare the numerators: 45 vs 64.
• Step 4. Since 45 is less than 64, we know that \(\frac{5}{8} < \frac{8}{9}\).

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: \(5 \times 9 = 45\).
• Step 2. Multiply the numerator of the second fraction by the denominator of the first: \(8 \times 8 = 64\).
• Step 3. Compare the products: \(45 < 64\), so \(\frac{5}{8} < \frac{8}{9}\).

Method 3: Decimal Comparison

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

Since 0.625 is less than 0.888889, we confirm that \(\frac{5}{8} < \frac{8}{9}\). In percentage terms, \(\frac{5}{8}\) is 62.5% and \(\frac{8}{9}\) is 88.8889%, a difference of 26.3889 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 72, we're cutting both quantities into equal-sized pieces. Then 45 pieces vs 64 pieces is a straightforward comparison.