Subtract 3/20 from 42/84
42/84 - 3/20 is 7/20.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 84 and 20 is 420
Next, find the equivalent fraction of both fractional numbers with denominator 420 - For the 1st fraction, since 84 × 5 = 420,
42/84 = 42 × 5/84 × 5 = 210/420 - Likewise, for the 2nd fraction, since 20 × 21 = 420,
3/20 = 3 × 21/20 × 21 = 63/420 - Subtract the two like fractions:
210/420 - 63/420 = 210 - 63/420 = 147/420 - After reducing the fraction, the answer is 7/20
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/84-6/20 42/84-3/40 42/84-9/20 42/84-3/60 42/84-15/20 42/84-21/20