Is 5/8 Bigger Than 9/10?

Method 1: Common Denominators

To compare these fractions, we need a common denominator. The denominators are 8 and 10, and the least common denominator (LCD) is 40.

• Step 1. Convert \(\frac{5}{8}\): multiply numerator and denominator by 5.
  \[\frac{5}{8} = \frac{5 \times 5}{8 \times 5} = \frac{25}{40}\]
• Step 2. Convert \(\frac{9}{10}\): multiply numerator and denominator by 4.
  \[\frac{9}{10} = \frac{9 \times 4}{10 \times 4} = \frac{36}{40}\]
• Step 3. Compare the numerators: 25 vs 36.
• Step 4. Since 25 is less than 36, we know that \(\frac{5}{8} < \frac{9}{10}\).

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: \(5 \times 10 = 50\).
• Step 2. Multiply the numerator of the second fraction by the denominator of the first: \(9 \times 8 = 72\).
• Step 3. Compare the products: \(50 < 72\), so \(\frac{5}{8} < \frac{9}{10}\).

Method 3: Decimal Comparison

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

Since 0.625 is less than 0.9, we confirm that \(\frac{5}{8} < \frac{9}{10}\). In percentage terms, \(\frac{5}{8}\) is 62.5% and \(\frac{9}{10}\) is 90%, a difference of 27.5 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 40, we're cutting both quantities into equal-sized pieces. Then 25 pieces vs 36 pieces is a straightforward comparison.