Subtract 21/72 from 20/90
20/90 - 21/72 is -5/72.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 90 and 72 is 360
Next, find the equivalent fraction of both fractional numbers with denominator 360 - For the 1st fraction, since 90 × 4 = 360,
20/90 = 20 × 4/90 × 4 = 80/360 - Likewise, for the 2nd fraction, since 72 × 5 = 360,
21/72 = 21 × 5/72 × 5 = 105/360 - Subtract the two like fractions:
80/360 - 105/360 = 80 - 105/360 = -25/360 - After reducing the fraction, the answer is -5/72
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