Subtract 40/70 from 80/90
80/90 - 40/70 is 20/63.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 90 and 70 is 630
Next, find the equivalent fraction of both fractional numbers with denominator 630 - For the 1st fraction, since 90 × 7 = 630,
80/90 = 80 × 7/90 × 7 = 560/630 - Likewise, for the 2nd fraction, since 70 × 9 = 630,
40/70 = 40 × 9/70 × 9 = 360/630 - Subtract the two like fractions:
560/630 - 360/630 = 560 - 360/630 = 200/630 - After reducing the fraction, the answer is 20/63
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 80/90-80/70