Subtract 4/5 from 21/72
21/72 - 4/5 is -61/120.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 72 and 5 is 360
Next, find the equivalent fraction of both fractional numbers with denominator 360 - For the 1st fraction, since 72 × 5 = 360,
21/72 = 21 × 5/72 × 5 = 105/360 - Likewise, for the 2nd fraction, since 5 × 72 = 360,
4/5 = 4 × 72/5 × 72 = 288/360 - Subtract the two like fractions:
105/360 - 288/360 = 105 - 288/360 = -183/360 - After reducing the fraction, the answer is -61/120
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