Subtract 10/21 from 90/20, Solve 4 10/20

Subtract 10/21 from 90/20

1^st number: 4 10/20, 2^nd number: 10/21

90/20 - 10/21 is 169/42.

Find the least common denominator or LCM of the two denominators:
LCM of 20 and 21 is 420

Next, find the equivalent fraction of both fractional numbers with denominator 420
For the 1st fraction, since 20 × 21 = 420,
90/20 = 90 × 21/20 × 21 = 1890/420
Likewise, for the 2nd fraction, since 21 × 20 = 420,
10/21 = 10 × 20/21 × 20 = 200/420
Subtract the two like fractions:
1890/420 - 200/420 = 1890 - 200/420 = 1690/420
After reducing the fraction, the answer is 169/42
In mixed form: 41/42

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