Subtract 70/21 from 2/90, Solve 2/90

Subtract 70/21 from 2/90

1^st number: 2/90, 2^nd number: 3 7/21

2/90 - 70/21 is -149/45.

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,
2/90 = 2 × 7/90 × 7 = 14/630
Likewise, for the 2nd fraction, since 21 × 30 = 630,
70/21 = 70 × 30/21 × 30 = 2100/630
Subtract the two like fractions:
14/630 - 2100/630 = 14 - 2100/630 = -2086/630
After reducing the fraction, the answer is -149/45

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