Answers

Subtract 72/40 from 20/90

1^st number: 20/90, 2^nd number: 1 32/40

20/90 - 72/40 is -71/45.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 90 and 40 is 360
   
   Next, find the equivalent fraction of both fractional numbers with denominator 360
2. For the 1st fraction, since 90 × 4 = 360,
   20/90 = 20 × 4/90 × 4 = 80/360
3. Likewise, for the 2nd fraction, since 40 × 9 = 360,
   72/40 = 72 × 9/40 × 9 = 648/360
4. Subtract the two like fractions:
   80/360 - 648/360 = 80 - 648/360 = -568/360
5. After reducing the fraction, the answer is -71/45

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