Is 2/3 Bigger Than 4/5?

Method 1: Common Denominators

To compare these fractions, we need a common denominator. The denominators are 3 and 5, and the least common denominator (LCD) is 15.

• Step 1. Convert \(\frac{2}{3}\): multiply numerator and denominator by 5.
  \[\frac{2}{3} = \frac{2 \times 5}{3 \times 5} = \frac{10}{15}\]
• Step 2. Convert \(\frac{4}{5}\): multiply numerator and denominator by 3.
  \[\frac{4}{5} = \frac{4 \times 3}{5 \times 3} = \frac{12}{15}\]
• Step 3. Compare the numerators: 10 vs 12.
• Step 4. Since 10 is less than 12, we know that \(\frac{2}{3} < \frac{4}{5}\).

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: \(2 \times 5 = 10\).
• Step 2. Multiply the numerator of the second fraction by the denominator of the first: \(4 \times 3 = 12\).
• Step 3. Compare the products: \(10 < 12\), so \(\frac{2}{3} < \frac{4}{5}\).

Method 3: Decimal Comparison

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

Since 0.666667 is less than 0.8, we confirm that \(\frac{2}{3} < \frac{4}{5}\). In percentage terms, \(\frac{2}{3}\) is 66.6667% and \(\frac{4}{5}\) is 80%, a difference of 13.3333 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 15, we're cutting both quantities into equal-sized pieces. Then 10 pieces vs 12 pieces is a straightforward comparison.