Subtract 42/12 from 7/45, Solve 7/45

Subtract 42/12 from 7/45

1^st number: 7/45, 2^nd number: 3 6/12

7/45 - 42/12 is -301/90.

Find the least common denominator or LCM of the two denominators:
LCM of 45 and 12 is 180

Next, find the equivalent fraction of both fractional numbers with denominator 180
For the 1st fraction, since 45 × 4 = 180,
7/45 = 7 × 4/45 × 4 = 28/180
Likewise, for the 2nd fraction, since 12 × 15 = 180,
42/12 = 42 × 15/12 × 15 = 630/180
Subtract the two like fractions:
28/180 - 630/180 = 28 - 630/180 = -602/180
After reducing the fraction, the answer is -301/90

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