Subtract 28/30 from 21/28
21/28 - 28/30 is -11/60.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 28 and 30 is 420
Next, find the equivalent fraction of both fractional numbers with denominator 420 - For the 1st fraction, since 28 × 15 = 420,
21/28 = 21 × 15/28 × 15 = 315/420 - Likewise, for the 2nd fraction, since 30 × 14 = 420,
28/30 = 28 × 14/30 × 14 = 392/420 - Subtract the two like fractions:
315/420 - 392/420 = 315 - 392/420 = -77/420 - After reducing the fraction, the answer is -11/60
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