Subtract 70/75 from 21/70, Solve 21/70

Subtract 70/75 from 21/70

21/70 - 70/75 is -19/30.

Find the least common denominator or LCM of the two denominators:
LCM of 70 and 75 is 1050

Next, find the equivalent fraction of both fractional numbers with denominator 1050
For the 1st fraction, since 70 × 15 = 1050,
21/70 = 21 × 15/70 × 15 = 315/1050
Likewise, for the 2nd fraction, since 75 × 14 = 1050,
70/75 = 70 × 14/75 × 14 = 980/1050
Subtract the two like fractions:
315/1050 - 980/1050 = 315 - 980/1050 = -665/1050
After reducing the fraction, the answer is -19/30

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