Subtract 80/21 from 50/90, Solve 50/90

Subtract 80/21 from 50/90

1^st number: 50/90, 2^nd number: 3 17/21

50/90 - 80/21 is -205/63.

Find the least common denominator or LCM of the two denominators:
LCM of 90 and 21 is 630

Next, find the equivalent fraction of both fractional numbers with denominator 630
For the 1st fraction, since 90 × 7 = 630,
50/90 = 50 × 7/90 × 7 = 350/630
Likewise, for the 2nd fraction, since 21 × 30 = 630,
80/21 = 80 × 30/21 × 30 = 2400/630
Subtract the two like fractions:
350/630 - 2400/630 = 350 - 2400/630 = -2050/630
After reducing the fraction, the answer is -205/63

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