Subtract 98/90 from 7/21, Solve 7/21

Subtract 98/90 from 7/21

1^st number: 7/21, 2^nd number: 1 8/90

7/21 - 98/90 is -34/45.

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

Next, find the equivalent fraction of both fractional numbers with denominator 630
For the 1st fraction, since 21 × 30 = 630,
7/21 = 7 × 30/21 × 30 = 210/630
Likewise, for the 2nd fraction, since 90 × 7 = 630,
98/90 = 98 × 7/90 × 7 = 686/630
Subtract the two like fractions:
210/630 - 686/630 = 210 - 686/630 = -476/630
After reducing the fraction, the answer is -34/45

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