Answers

Subtract 21/20 from 90/72

1^st number: 1 18/72, 2^nd number: 1 1/20

90/72 - 21/20 is 1/5.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 72 and 20 is 360
   
   Next, find the equivalent fraction of both fractional numbers with denominator 360
2. For the 1st fraction, since 72 × 5 = 360,
   90/72 = 90 × 5/72 × 5 = 450/360
3. Likewise, for the 2nd fraction, since 20 × 18 = 360,
   21/20 = 21 × 18/20 × 18 = 378/360
4. Subtract the two like fractions:
   450/360 - 378/360 = 450 - 378/360 = 72/360
5. After reducing the fraction, the answer is 1/5

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