Subtract 90/21 from 81/40
1st number: 2 1/40, 2nd number: 4 6/21
81/40 - 90/21 is -633/280.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 40 and 21 is 840
Next, find the equivalent fraction of both fractional numbers with denominator 840 - For the 1st fraction, since 40 × 21 = 840,
81/40 = 81 × 21/40 × 21 = 1701/840 - Likewise, for the 2nd fraction, since 21 × 40 = 840,
90/21 = 90 × 40/21 × 40 = 3600/840 - Subtract the two like fractions:
1701/840 - 3600/840 = 1701 - 3600/840 = -1899/840 - After reducing the fraction, the answer is -633/280
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