Subtract 4/5 from 9/42, Solve 9/42

Subtract 4/5 from 9/42

9/42 - 4/5 is -41/70.

Find the least common denominator or LCM of the two denominators:
LCM of 42 and 5 is 210

Next, find the equivalent fraction of both fractional numbers with denominator 210
For the 1st fraction, since 42 × 5 = 210,
9/42 = 9 × 5/42 × 5 = 45/210
Likewise, for the 2nd fraction, since 5 × 42 = 210,
4/5 = 4 × 42/5 × 42 = 168/210
Subtract the two like fractions:
45/210 - 168/210 = 45 - 168/210 = -123/210
After reducing the fraction, the answer is -41/70

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