Add 90/20 and 8/21
1st number: 4 10/20, 2nd number: 8/21
90/20 + 8/21 is 205/42.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 20 and 21 is 420
Next, find the equivalent fraction of both fractional numbers with denominator 420 - For the 1st fraction, since 20 × 21 = 420,
90/20 = 90 × 21/20 × 21 = 1890/420 - Likewise, for the 2nd fraction, since 21 × 20 = 420,
8/21 = 8 × 20/21 × 20 = 160/420 - Add the two like fractions:
1890/420 + 160/420 = 1890 + 160/420 = 2050/420 - 2050/420 simplified gives 205/42
- So, 90/20 + 8/21 = 205/42
In mixed form: 437/42
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 90/20+16/21 90/40+8/21 90/20+8/42 90/20+24/21 90/60+8/21 90/20+8/63 90/20+40/21 90/20+56/21