Compare Fractions Fast
Decide which of two fractions is larger without a common denominator.
Compare a/b and c/d by cross-multiplying: a×d vs b×c.
1How it works
To compare two fractions, cross-multiply and compare the products. The fraction on the side of the larger product is the bigger one.
2How to apply (in seconds)
- For a/b and c/d, compute a×d and b×c.
- Whichever cross-product is larger marks the larger fraction.
3Worked examples
Example 1 Worked solution
Q. Which is larger: 5/8 or 7/11?
- 5 × 11 = 55 and 8 × 7 = 56.
- 56 > 55, so the 7/11 side is larger.
✓ 7/11 is larger
4When to use it
- ✦Ordering fractions and picking the biggest or smallest option.
5Cautions & tips
- !Keep the fractions in the same left-to-right order while cross-multiplying.