Subtract 9/12 from 42/80
42/80 - 9/12 is -9/40.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 80 and 12 is 240
Next, find the equivalent fraction of both fractional numbers with denominator 240 - For the 1st fraction, since 80 × 3 = 240,
42/80 = 42 × 3/80 × 3 = 126/240 - Likewise, for the 2nd fraction, since 12 × 20 = 240,
9/12 = 9 × 20/12 × 20 = 180/240 - Subtract the two like fractions:
126/240 - 180/240 = 126 - 180/240 = -54/240 - After reducing the fraction, the answer is -9/40
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 84/80-9/12 42/80-18/12 42/80-9/24 42/80-27/12 42/80-9/36 42/80-45/12 42/80-9/60 42/80-63/12 42/80-9/84