Subtract 90/72 from 4/5, Solve 4/5 - 1 18/72 as a fraction

Subtract 90/72 from 4/5

1^st number: 4/5, 2^nd number: 1 18/72

4/5 - 90/72 is -9/20.

Find the least common denominator or LCM of the two denominators:
LCM of 5 and 72 is 360

Next, find the equivalent fraction of both fractional numbers with denominator 360
For the 1st fraction, since 5 × 72 = 360,
4/5 = 4 × 72/5 × 72 = 288/360
Likewise, for the 2nd fraction, since 72 × 5 = 360,
90/72 = 90 × 5/72 × 5 = 450/360
Subtract the two like fractions:
288/360 - 450/360 = 288 - 450/360 = -162/360
After reducing the fraction, the answer is -9/20

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