Subtract 21/9 from 72/70, Solve 1 2/70

Subtract 21/9 from 72/70

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

72/70 - 21/9 is -137/105.

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,
72/70 = 72 × 9/70 × 9 = 648/630
Likewise, for the 2nd fraction, since 9 × 70 = 630,
21/9 = 21 × 70/9 × 70 = 1470/630
Subtract the two like fractions:
648/630 - 1470/630 = 648 - 1470/630 = -822/630
After reducing the fraction, the answer is -137/105

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