Answers

Subtract 60/21 from 90/40

1^st number: 2 10/40, 2^nd number: 2 18/21

90/40 - 60/21 is -17/28.

Steps for subtracting fractions

1. 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
2. For the 1st fraction, since 40 × 21 = 840,
   90/40 = 90 × 21/40 × 21 = 1890/840
3. Likewise, for the 2nd fraction, since 21 × 40 = 840,
   60/21 = 60 × 40/21 × 40 = 2400/840
4. Subtract the two like fractions:
   1890/840 - 2400/840 = 1890 - 2400/840 = -510/840
5. After reducing the fraction, the answer is -17/28

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