Subtract 1/90 from 42/81
42/81 - 1/90 is 137/270.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 81 and 90 is 810
Next, find the equivalent fraction of both fractional numbers with denominator 810 - For the 1st fraction, since 81 × 10 = 810,
42/81 = 42 × 10/81 × 10 = 420/810 - Likewise, for the 2nd fraction, since 90 × 9 = 810,
1/90 = 1 × 9/90 × 9 = 9/810 - Subtract the two like fractions:
420/810 - 9/810 = 420 - 9/810 = 411/810 - After reducing the fraction, the answer is 137/270
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