Is 2/5 Bigger Than 5/9?

Method 1: Common Denominators

To compare these fractions, we need a common denominator. The denominators are 5 and 9, and the least common denominator (LCD) is 45.

• Step 1. Convert \(\frac{2}{5}\): multiply numerator and denominator by 9.
  \[\frac{2}{5} = \frac{2 \times 9}{5 \times 9} = \frac{18}{45}\]
• Step 2. Convert \(\frac{5}{9}\): multiply numerator and denominator by 5.
  \[\frac{5}{9} = \frac{5 \times 5}{9 \times 5} = \frac{25}{45}\]
• Step 3. Compare the numerators: 18 vs 25.
• Step 4. Since 18 is less than 25, we know that \(\frac{2}{5} < \frac{5}{9}\).

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: \(2 \times 9 = 18\).
• Step 2. Multiply the numerator of the second fraction by the denominator of the first: \(5 \times 5 = 25\).
• Step 3. Compare the products: \(18 < 25\), so \(\frac{2}{5} < \frac{5}{9}\).

Method 3: Decimal Comparison

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

Since 0.4 is less than 0.555556, we confirm that \(\frac{2}{5} < \frac{5}{9}\). In percentage terms, \(\frac{2}{5}\) is 40% and \(\frac{5}{9}\) is 55.5556%, a difference of 15.5556 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 45, we're cutting both quantities into equal-sized pieces. Then 18 pieces vs 25 pieces is a straightforward comparison.