Subtract 30/90 from 20/70
20/70 - 30/90 is -1/21.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 70 and 90 is 630
Next, find the equivalent fraction of both fractional numbers with denominator 630 - For the 1st fraction, since 70 × 9 = 630,
20/70 = 20 × 9/70 × 9 = 180/630 - Likewise, for the 2nd fraction, since 90 × 7 = 630,
30/90 = 30 × 7/90 × 7 = 210/630 - Subtract the two like fractions:
180/630 - 210/630 = 180 - 210/630 = -30/630 - After reducing the fraction, the answer is -1/21
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