Subtract 56/21 from 15/90, Solve 15/90

Subtract 56/21 from 15/90

1^st number: 15/90, 2^nd number: 2 14/21

15/90 - 56/21 is -5/2.

Find the least common denominator or LCM of the two denominators:
LCM of 90 and 21 is 630

Next, find the equivalent fraction of both fractional numbers with denominator 630
For the 1st fraction, since 90 × 7 = 630,
15/90 = 15 × 7/90 × 7 = 105/630
Likewise, for the 2nd fraction, since 21 × 30 = 630,
56/21 = 56 × 30/21 × 30 = 1680/630
Subtract the two like fractions:
105/630 - 1680/630 = 105 - 1680/630 = -1575/630
After reducing the fraction, the answer is -5/2

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