Subtract 21/20 from 42/72
1st number: 42/72, 2nd number: 1 1/20
42/72 - 21/20 is -7/15.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 72 and 20 is 360
Next, find the equivalent fraction of both fractional numbers with denominator 360 - For the 1st fraction, since 72 × 5 = 360,
42/72 = 42 × 5/72 × 5 = 210/360 - Likewise, for the 2nd fraction, since 20 × 18 = 360,
21/20 = 21 × 18/20 × 18 = 378/360 - Subtract the two like fractions:
210/360 - 378/360 = 210 - 378/360 = -168/360 - After reducing the fraction, the answer is -7/15
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