Subtract 18/12 from 90/70, Solve 1 20/70

Subtract 18/12 from 90/70

1^st number: 1 20/70, 2^nd number: 1 6/12

90/70 - 18/12 is -3/14.

Find the least common denominator or LCM of the two denominators:
LCM of 70 and 12 is 420

Next, find the equivalent fraction of both fractional numbers with denominator 420
For the 1st fraction, since 70 × 6 = 420,
90/70 = 90 × 6/70 × 6 = 540/420
Likewise, for the 2nd fraction, since 12 × 35 = 420,
18/12 = 18 × 35/12 × 35 = 630/420
Subtract the two like fractions:
540/420 - 630/420 = 540 - 630/420 = -90/420
After reducing the fraction, the answer is -3/14

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