Add 21/72 and 21/90
21/72 + 21/90 is 21/40.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 72 and 90 is 360
Next, find the equivalent fraction of both fractional numbers with denominator 360 - For the 1st fraction, since 72 × 5 = 360,
21/72 = 21 × 5/72 × 5 = 105/360 - Likewise, for the 2nd fraction, since 90 × 4 = 360,
21/90 = 21 × 4/90 × 4 = 84/360 - Add the two like fractions:
105/360 + 84/360 = 105 + 84/360 = 189/360 - 189/360 simplified gives 21/40
- So, 21/72 + 21/90 = 21/40
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