Is 8/9 Bigger Than 7/10?

Method 1: Common Denominators

To compare these fractions, we need a common denominator. The denominators are 9 and 10, and the least common denominator (LCD) is 90.

• Step 1. Convert \(\frac{8}{9}\): multiply numerator and denominator by 10.
  \[\frac{8}{9} = \frac{8 \times 10}{9 \times 10} = \frac{80}{90}\]
• Step 2. Convert \(\frac{7}{10}\): multiply numerator and denominator by 9.
  \[\frac{7}{10} = \frac{7 \times 9}{10 \times 9} = \frac{63}{90}\]
• Step 3. Compare the numerators: 80 vs 63.
• Step 4. Since 80 is greater than 63, we know that \(\frac{8}{9} > \frac{7}{10}\).

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: \(8 \times 10 = 80\).
• Step 2. Multiply the numerator of the second fraction by the denominator of the first: \(7 \times 9 = 63\).
• Step 3. Compare the products: \(80 > 63\), so \(\frac{8}{9} > \frac{7}{10}\).

Method 3: Decimal Comparison

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

Since 0.888889 is greater than 0.7, we confirm that \(\frac{8}{9} > \frac{7}{10}\). In percentage terms, \(\frac{8}{9}\) is 88.8889% and \(\frac{7}{10}\) is 70%, a difference of 18.8889 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 90, we're cutting both quantities into equal-sized pieces. Then 80 pieces vs 63 pieces is a straightforward comparison.