Subtract 21/80 from 84/90, Solve 84/90

Subtract 21/80 from 84/90

84/90 - 21/80 is 161/240.

Find the least common denominator or LCM of the two denominators:
LCM of 90 and 80 is 720

Next, find the equivalent fraction of both fractional numbers with denominator 720
For the 1st fraction, since 90 × 8 = 720,
84/90 = 84 × 8/90 × 8 = 672/720
Likewise, for the 2nd fraction, since 80 × 9 = 720,
21/80 = 21 × 9/80 × 9 = 189/720
Subtract the two like fractions:
672/720 - 189/720 = 672 - 189/720 = 483/720
After reducing the fraction, the answer is 161/240

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