Subtract 21/54 from 81/80, Solve 1 1/80

Subtract 21/54 from 81/80

1^st number: 1 1/80, 2^nd number: 21/54

81/80 - 21/54 is 449/720.

Find the least common denominator or LCM of the two denominators:
LCM of 80 and 54 is 2160

Next, find the equivalent fraction of both fractional numbers with denominator 2160
For the 1st fraction, since 80 × 27 = 2160,
81/80 = 81 × 27/80 × 27 = 2187/2160
Likewise, for the 2nd fraction, since 54 × 40 = 2160,
21/54 = 21 × 40/54 × 40 = 840/2160
Subtract the two like fractions:
2187/2160 - 840/2160 = 2187 - 840/2160 = 1347/2160
After reducing the fraction, the answer is 449/720

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