Subtract 81/40 from 45/21, Solve 2 3/21

Subtract 81/40 from 45/21

1^st number: 2 3/21, 2^nd number: 2 1/40

45/21 - 81/40 is 33/280.

Find the least common denominator or LCM of the two denominators:
LCM of 21 and 40 is 840

Next, find the equivalent fraction of both fractional numbers with denominator 840
For the 1st fraction, since 21 × 40 = 840,
45/21 = 45 × 40/21 × 40 = 1800/840
Likewise, for the 2nd fraction, since 40 × 21 = 840,
81/40 = 81 × 21/40 × 21 = 1701/840
Subtract the two like fractions:
1800/840 - 1701/840 = 1800 - 1701/840 = 99/840
After reducing the fraction, the answer is 33/280

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