Answers

Subtract 5/42 from 21/40

21/40 - 5/42 is 341/840.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 40 and 42 is 840
   
   Next, find the equivalent fraction of both fractional numbers with denominator 840
2. For the 1st fraction, since 40 × 21 = 840,
   21/40 = 21 × 21/40 × 21 = 441/840
3. Likewise, for the 2nd fraction, since 42 × 20 = 840,
   5/42 = 5 × 20/42 × 20 = 100/840
4. Subtract the two like fractions:
   441/840 - 100/840 = 441 - 100/840 = 341/840

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