Subtract 18/20 from 21/70
21/70 - 18/20 is -3/5.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 70 and 20 is 140
Next, find the equivalent fraction of both fractional numbers with denominator 140 - For the 1st fraction, since 70 × 2 = 140,
21/70 = 21 × 2/70 × 2 = 42/140 - Likewise, for the 2nd fraction, since 20 × 7 = 140,
18/20 = 18 × 7/20 × 7 = 126/140 - Subtract the two like fractions:
42/140 - 126/140 = 42 - 126/140 = -84/140 - After reducing the fraction, the answer is -3/5
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