Answers

Subtract 90/27 from 20/21

1^st number: 20/21, 2^nd number: 3 9/27

20/21 - 90/27 is -50/21.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 21 and 27 is 189
   
   Next, find the equivalent fraction of both fractional numbers with denominator 189
2. For the 1st fraction, since 21 × 9 = 189,
   20/21 = 20 × 9/21 × 9 = 180/189
3. Likewise, for the 2nd fraction, since 27 × 7 = 189,
   90/27 = 90 × 7/27 × 7 = 630/189
4. Subtract the two like fractions:
   180/189 - 630/189 = 180 - 630/189 = -450/189
5. After reducing the fraction, the answer is -50/21

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