Subtract 9/20 from 70/21, Solve 3 7/21

Subtract 9/20 from 70/21

1^st number: 3 7/21, 2^nd number: 9/20

70/21 - 9/20 is 173/60.

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

Next, find the equivalent fraction of both fractional numbers with denominator 420
For the 1st fraction, since 21 × 20 = 420,
70/21 = 70 × 20/21 × 20 = 1400/420
Likewise, for the 2nd fraction, since 20 × 21 = 420,
9/20 = 9 × 21/20 × 21 = 189/420
Subtract the two like fractions:
1400/420 - 189/420 = 1400 - 189/420 = 1211/420
After reducing the fraction, the answer is 173/60
In mixed form: 253/60

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