Subtract 84/40 from 12/30, Solve 12/30

Subtract 84/40 from 12/30

1^st number: 12/30, 2^nd number: 2 4/40

12/30 - 84/40 is -17/10.

Find the least common denominator or LCM of the two denominators:
LCM of 30 and 40 is 120

Next, find the equivalent fraction of both fractional numbers with denominator 120
For the 1st fraction, since 30 × 4 = 120,
12/30 = 12 × 4/30 × 4 = 48/120
Likewise, for the 2nd fraction, since 40 × 3 = 120,
84/40 = 84 × 3/40 × 3 = 252/120
Subtract the two like fractions:
48/120 - 252/120 = 48 - 252/120 = -204/120
After reducing the fraction, the answer is -17/10

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