Add 72/80 and 21/90
72/80 + 21/90 is 17/15.
Steps for adding fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 80 and 90 is 720
Next, find the equivalent fraction of both fractional numbers with denominator 720 - For the 1st fraction, since 80 × 9 = 720,
72/80 = 72 × 9/80 × 9 = 648/720 - Likewise, for the 2nd fraction, since 90 × 8 = 720,
21/90 = 21 × 8/90 × 8 = 168/720 - Add the two like fractions:
648/720 + 168/720 = 648 + 168/720 = 816/720 - 816/720 simplified gives 17/15
- So, 72/80 + 21/90 = 17/15
In mixed form: 12/15
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