Subtract 21/80 from 84/18, Solve 4 12/18

Subtract 21/80 from 84/18

1^st number: 4 12/18, 2^nd number: 21/80

84/18 - 21/80 is 1057/240.

Find the least common denominator or LCM of the two denominators:
LCM of 18 and 80 is 720

Next, find the equivalent fraction of both fractional numbers with denominator 720
For the 1st fraction, since 18 × 40 = 720,
84/18 = 84 × 40/18 × 40 = 3360/720
Likewise, for the 2nd fraction, since 80 × 9 = 720,
21/80 = 21 × 9/80 × 9 = 189/720
Subtract the two like fractions:
3360/720 - 189/720 = 3360 - 189/720 = 3171/720
After reducing the fraction, the answer is 1057/240
In mixed form: 497/240

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