Answers

Subtract 70/21 from 20/40

1^st number: 20/40, 2^nd number: 3 7/21

20/40 - 70/21 is -17/6.

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,
   20/40 = 20 × 21/40 × 21 = 420/840
3. Likewise, for the 2nd fraction, since 21 × 40 = 840,
   70/21 = 70 × 40/21 × 40 = 2800/840
4. Subtract the two like fractions:
   420/840 - 2800/840 = 420 - 2800/840 = -2380/840
5. After reducing the fraction, the answer is -17/6

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