Subtract 15/8 from 81/18, Solve 4 9/18

Subtract 15/8 from 81/18

1^st number: 4 9/18, 2^nd number: 1 7/8

81/18 - 15/8 is 21/8.

Find the least common denominator or LCM of the two denominators:
LCM of 18 and 8 is 72

Next, find the equivalent fraction of both fractional numbers with denominator 72
For the 1st fraction, since 18 × 4 = 72,
81/18 = 81 × 4/18 × 4 = 324/72
Likewise, for the 2nd fraction, since 8 × 9 = 72,
15/8 = 15 × 9/8 × 9 = 135/72
Subtract the two like fractions:
324/72 - 135/72 = 324 - 135/72 = 189/72
After reducing the fraction, the answer is 21/8
In mixed form: 25/8

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