Subtract 7/10 from 90/72, Solve 1 18/72

Subtract 7/10 from 90/72

1^st number: 1 18/72, 2^nd number: 7/10

90/72 - 7/10 is 11/20.

Find the least common denominator or LCM of the two denominators:
LCM of 72 and 10 is 360

Next, find the equivalent fraction of both fractional numbers with denominator 360
For the 1st fraction, since 72 × 5 = 360,
90/72 = 90 × 5/72 × 5 = 450/360
Likewise, for the 2nd fraction, since 10 × 36 = 360,
7/10 = 7 × 36/10 × 36 = 252/360
Subtract the two like fractions:
450/360 - 252/360 = 450 - 252/360 = 198/360
After reducing the fraction, the answer is 11/20

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