Subtract 81/45 from 10/21, Solve 10/21

Subtract 81/45 from 10/21

1^st number: 10/21, 2^nd number: 1 36/45

10/21 - 81/45 is -139/105.

Find the least common denominator or LCM of the two denominators:
LCM of 21 and 45 is 315

Next, find the equivalent fraction of both fractional numbers with denominator 315
For the 1st fraction, since 21 × 15 = 315,
10/21 = 10 × 15/21 × 15 = 150/315
Likewise, for the 2nd fraction, since 45 × 7 = 315,
81/45 = 81 × 7/45 × 7 = 567/315
Subtract the two like fractions:
150/315 - 567/315 = 150 - 567/315 = -417/315
After reducing the fraction, the answer is -139/105

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