Is 1/3 Bigger Than 2/7?

Method 1: Common Denominators

To compare these fractions, we need a common denominator. The denominators are 3 and 7, and the least common denominator (LCD) is 21.

• Step 1. Convert \(\frac{1}{3}\): multiply numerator and denominator by 7.
  \[\frac{1}{3} = \frac{1 \times 7}{3 \times 7} = \frac{7}{21}\]
• Step 2. Convert \(\frac{2}{7}\): multiply numerator and denominator by 3.
  \[\frac{2}{7} = \frac{2 \times 3}{7 \times 3} = \frac{6}{21}\]
• Step 3. Compare the numerators: 7 vs 6.
• Step 4. Since 7 is greater than 6, we know that \(\frac{1}{3} > \frac{2}{7}\).

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: \(1 \times 7 = 7\).
• Step 2. Multiply the numerator of the second fraction by the denominator of the first: \(2 \times 3 = 6\).
• Step 3. Compare the products: \(7 > 6\), so \(\frac{1}{3} > \frac{2}{7}\).

Method 3: Decimal Comparison

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

Since 0.333333 is greater than 0.285714, we confirm that \(\frac{1}{3} > \frac{2}{7}\). In percentage terms, \(\frac{1}{3}\) is 33.3333% and \(\frac{2}{7}\) is 28.5714%, a difference of 4.7619 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 21, we're cutting both quantities into equal-sized pieces. Then 7 pieces vs 6 pieces is a straightforward comparison.