Subtract 2/20 from 15/21, Solve 15/21

Subtract 2/20 from 15/21

15/21 - 2/20 is 43/70.

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,
15/21 = 15 × 20/21 × 20 = 300/420
Likewise, for the 2nd fraction, since 20 × 21 = 420,
2/20 = 2 × 21/20 × 21 = 42/420
Subtract the two like fractions:
300/420 - 42/420 = 300 - 42/420 = 258/420
After reducing the fraction, the answer is 43/70

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