Add 72/21 and 12/40
1st number: 3 9/21, 2nd number: 12/40
72/21 + 12/40 is 261/70.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 40 is 840
Next, find the equivalent fraction of both fractional numbers with denominator 840 - For the 1st fraction, since 21 × 40 = 840,
72/21 = 72 × 40/21 × 40 = 2880/840 - Likewise, for the 2nd fraction, since 40 × 21 = 840,
12/40 = 12 × 21/40 × 21 = 252/840 - Add the two like fractions:
2880/840 + 252/840 = 2880 + 252/840 = 3132/840 - 3132/840 simplified gives 261/70
- So, 72/21 + 12/40 = 261/70
In mixed form: 351/70
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 72/21+24/40 72/42+12/40 72/21+12/80 72/21+36/40 72/63+12/40 72/21+60/40 72/21+84/40