Subtract 18/21 from 21/30
21/30 - 18/21 is -11/70.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 30 and 21 is 210
Next, find the equivalent fraction of both fractional numbers with denominator 210 - For the 1st fraction, since 30 × 7 = 210,
21/30 = 21 × 7/30 × 7 = 147/210 - Likewise, for the 2nd fraction, since 21 × 10 = 210,
18/21 = 18 × 10/21 × 10 = 180/210 - Subtract the two like fractions:
147/210 - 180/210 = 147 - 180/210 = -33/210 - After reducing the fraction, the answer is -11/70
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