Answers

Subtract 16/45 from 21/80

21/80 - 16/45 is -67/720.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 80 and 45 is 720
   
   Next, find the equivalent fraction of both fractional numbers with denominator 720
2. For the 1st fraction, since 80 × 9 = 720,
   21/80 = 21 × 9/80 × 9 = 189/720
3. Likewise, for the 2nd fraction, since 45 × 16 = 720,
   16/45 = 16 × 16/45 × 16 = 256/720
4. Subtract the two like fractions:
   189/720 - 256/720 = 189 - 256/720 = -67/720

MathStep (Works offline)

Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad

Related: ⁴²/₈₀-¹⁶/₄₅ ²¹/₈₀-³²/₄₅ ²¹/₈₀-¹⁶/₉₀ ⁶³/₈₀-¹⁶/₄₅ ²¹/₈₀-⁴⁸/₄₅ ²¹/₈₀-⁸⁰/₄₅

Subtract Fractions Calculator