Add 15/40 and 12/21
15/40 + 12/21 is 53/56.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 40 and 21 is 840
Next, find the equivalent fraction of both fractional numbers with denominator 840 - For the 1st fraction, since 40 × 21 = 840,
15/40 = 15 × 21/40 × 21 = 315/840 - Likewise, for the 2nd fraction, since 21 × 40 = 840,
12/21 = 12 × 40/21 × 40 = 480/840 - Add the two like fractions:
315/840 + 480/840 = 315 + 480/840 = 795/840 - 795/840 simplified gives 53/56
- So, 15/40 + 12/21 = 53/56
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 30/40+12/21 15/40+24/21 15/80+12/21 15/40+12/42 45/40+12/21 15/40+36/21 15/40+12/63 75/40+12/21 15/40+60/21 15/40+84/21