Subtract 9/42 from 21/30
21/30 - 9/42 is 17/35.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 30 and 42 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 42 × 5 = 210,
9/42 = 9 × 5/42 × 5 = 45/210 - Subtract the two like fractions:
147/210 - 45/210 = 147 - 45/210 = 102/210 - After reducing the fraction, the answer is 17/35
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