Answers

Subtract 90/72 from 30/70

1^st number: 30/70, 2^nd number: 1 18/72

30/70 - 90/72 is -23/28.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 70 and 72 is 2520
   
   Next, find the equivalent fraction of both fractional numbers with denominator 2520
2. For the 1st fraction, since 70 × 36 = 2520,
   30/70 = 30 × 36/70 × 36 = 1080/2520
3. Likewise, for the 2nd fraction, since 72 × 35 = 2520,
   90/72 = 90 × 35/72 × 35 = 3150/2520
4. Subtract the two like fractions:
   1080/2520 - 3150/2520 = 1080 - 3150/2520 = -2070/2520
5. After reducing the fraction, the answer is -23/28

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