Subtract 30/8 from 20/70, Solve 20/70

Subtract 30/8 from 20/70

1^st number: 20/70, 2^nd number: 3 6/8

20/70 - 30/8 is -97/28.

Find the least common denominator or LCM of the two denominators:
LCM of 70 and 8 is 280

Next, find the equivalent fraction of both fractional numbers with denominator 280
For the 1st fraction, since 70 × 4 = 280,
20/70 = 20 × 4/70 × 4 = 80/280
Likewise, for the 2nd fraction, since 8 × 35 = 280,
30/8 = 30 × 35/8 × 35 = 1050/280
Subtract the two like fractions:
80/280 - 1050/280 = 80 - 1050/280 = -970/280
After reducing the fraction, the answer is -97/28

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