Subtract 10/5 from 9/21, Solve 9/21

Subtract 10/5 from 9/21

1^st number: 9/21, 2^nd number: 2 0/5

9/21 - 10/5 is -11/7.

Find the least common denominator or LCM of the two denominators:
LCM of 21 and 5 is 105

Next, find the equivalent fraction of both fractional numbers with denominator 105
For the 1st fraction, since 21 × 5 = 105,
9/21 = 9 × 5/21 × 5 = 45/105
Likewise, for the 2nd fraction, since 5 × 21 = 105,
10/5 = 10 × 21/5 × 21 = 210/105
Subtract the two like fractions:
45/105 - 210/105 = 45 - 210/105 = -165/105
After reducing the fraction, the answer is -11/7

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