Subtract 45/70 from 5/21
5/21 - 45/70 is -17/42.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 70 is 210
Next, find the equivalent fraction of both fractional numbers with denominator 210 - For the 1st fraction, since 21 × 10 = 210,
5/21 = 5 × 10/21 × 10 = 50/210 - Likewise, for the 2nd fraction, since 70 × 3 = 210,
45/70 = 45 × 3/70 × 3 = 135/210 - Subtract the two like fractions:
50/210 - 135/210 = 50 - 135/210 = -85/210 - After reducing the fraction, the answer is -17/42
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