Add 21/40 and 28/21
1st number: 21/40, 2nd number: 1 7/21
21/40 + 28/21 is 223/120.
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,
21/40 = 21 × 21/40 × 21 = 441/840 - Likewise, for the 2nd fraction, since 21 × 40 = 840,
28/21 = 28 × 40/21 × 40 = 1120/840 - Add the two like fractions:
441/840 + 1120/840 = 441 + 1120/840 = 1561/840 - 1561/840 simplified gives 223/120
- So, 21/40 + 28/21 = 223/120
In mixed form: 1103/120
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