Add 90/21 and 54/20
1st number: 4 6/21, 2nd number: 2 14/20
90/21 + 54/20 is 489/70.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 20 is 420
Next, find the equivalent fraction of both fractional numbers with denominator 420 - For the 1st fraction, since 21 × 20 = 420,
90/21 = 90 × 20/21 × 20 = 1800/420 - Likewise, for the 2nd fraction, since 20 × 21 = 420,
54/20 = 54 × 21/20 × 21 = 1134/420 - Add the two like fractions:
1800/420 + 1134/420 = 1800 + 1134/420 = 2934/420 - 2934/420 simplified gives 489/70
- So, 90/21 + 54/20 = 489/70
In mixed form: 669/70
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 90/42+54/20 90/21+54/40 90/63+54/20 90/21+54/60