Is 1/5 Bigger Than 1/8?

Method 1: Common Denominators

To compare these fractions, we need a common denominator. The denominators are 5 and 8, and the least common denominator (LCD) is 40.

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

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

Method 3: Decimal Comparison

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

Since 0.2 is greater than 0.125, we confirm that \(\frac{1}{5} > \frac{1}{8}\). In percentage terms, \(\frac{1}{5}\) is 20% and \(\frac{1}{8}\) is 12.5%, a difference of 7.5 percentage points.

Why Does This Work?

When two fractions have the same numerator, you have the same number of pieces — but the pieces are different sizes. A smaller denominator means each piece is larger. Since 8ths are larger pieces than 5ths, \(\frac{1}{5}\) is the bigger fraction even though both have 1 in the numerator.