Subtract 50/21 from 90/40
1st number: 2 10/40, 2nd number: 2 8/21
90/40 - 50/21 is -11/84.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 40 and 21 is 840
Next, find the equivalent fraction of both fractional numbers with denominator 840 - For the 1st fraction, since 40 × 21 = 840,
90/40 = 90 × 21/40 × 21 = 1890/840 - Likewise, for the 2nd fraction, since 21 × 40 = 840,
50/21 = 50 × 40/21 × 40 = 2000/840 - Subtract the two like fractions:
1890/840 - 2000/840 = 1890 - 2000/840 = -110/840 - After reducing the fraction, the answer is -11/84
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 90/80-50/21 90/40-50/42 90/40-50/63