Add 3/21 and 30/40
3/21 + 30/40 is 25/28.
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,
3/21 = 3 × 40/21 × 40 = 120/840 - Likewise, for the 2nd fraction, since 40 × 21 = 840,
30/40 = 30 × 21/40 × 21 = 630/840 - Add the two like fractions:
120/840 + 630/840 = 120 + 630/840 = 750/840 - 750/840 simplified gives 25/28
- So, 3/21 + 30/40 = 25/28
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 6/21+30/40 3/21+60/40 3/42+30/40 3/21+30/80 9/21+30/40 3/21+90/40 3/63+30/40 15/21+30/40