Subtract 9/42 from 30/40
30/40 - 9/42 is 15/28.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 40 and 42 is 840
Next, find the equivalent fraction of both fractional numbers with denominator 840 - For the 1st fraction, since 40 × 21 = 840,
30/40 = 30 × 21/40 × 21 = 630/840 - Likewise, for the 2nd fraction, since 42 × 20 = 840,
9/42 = 9 × 20/42 × 20 = 180/840 - Subtract the two like fractions:
630/840 - 180/840 = 630 - 180/840 = 450/840 - After reducing the fraction, the answer is 15/28
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 60/40-9/42 30/40-18/42 30/80-9/42 30/40-9/84 90/40-9/42 30/40-27/42 30/40-45/42 30/40-63/42