Subtract 21/9 from 15/70, Solve 15/70

Subtract 21/9 from 15/70

1^st number: 15/70, 2^nd number: 2 3/9

15/70 - 21/9 is -89/42.

Find the least common denominator or LCM of the two denominators:
LCM of 70 and 9 is 630

Next, find the equivalent fraction of both fractional numbers with denominator 630
For the 1st fraction, since 70 × 9 = 630,
15/70 = 15 × 9/70 × 9 = 135/630
Likewise, for the 2nd fraction, since 9 × 70 = 630,
21/9 = 21 × 70/9 × 70 = 1470/630
Subtract the two like fractions:
135/630 - 1470/630 = 135 - 1470/630 = -1335/630
After reducing the fraction, the answer is -89/42

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