Subtract 20/7 from 30/80, Solve 30/80

Subtract 20/7 from 30/80

1^st number: 30/80, 2^nd number: 2 6/7

30/80 - 20/7 is -139/56.

Find the least common denominator or LCM of the two denominators:
LCM of 80 and 7 is 560

Next, find the equivalent fraction of both fractional numbers with denominator 560
For the 1st fraction, since 80 × 7 = 560,
30/80 = 30 × 7/80 × 7 = 210/560
Likewise, for the 2nd fraction, since 7 × 80 = 560,
20/7 = 20 × 80/7 × 80 = 1600/560
Subtract the two like fractions:
210/560 - 1600/560 = 210 - 1600/560 = -1390/560
After reducing the fraction, the answer is -139/56

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