Subtract 75/45 from 21/70, Solve 21/70

Subtract 75/45 from 21/70

1^st number: 21/70, 2^nd number: 1 30/45

21/70 - 75/45 is -41/30.

Find the least common denominator or LCM of the two denominators:
LCM of 70 and 45 is 630

Next, find the equivalent fraction of both fractional numbers with denominator 630
For the 1st fraction, since 70 × 9 = 630,
21/70 = 21 × 9/70 × 9 = 189/630
Likewise, for the 2nd fraction, since 45 × 14 = 630,
75/45 = 75 × 14/45 × 14 = 1050/630
Subtract the two like fractions:
189/630 - 1050/630 = 189 - 1050/630 = -861/630
After reducing the fraction, the answer is -41/30

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