Subtract 1/80 from 63/42, Solve 1 21/42

Subtract 1/80 from 63/42

1^st number: 1 21/42, 2^nd number: 1/80

63/42 - 1/80 is 119/80.

Find the least common denominator or LCM of the two denominators:
LCM of 42 and 80 is 1680

Next, find the equivalent fraction of both fractional numbers with denominator 1680
For the 1st fraction, since 42 × 40 = 1680,
63/42 = 63 × 40/42 × 40 = 2520/1680
Likewise, for the 2nd fraction, since 80 × 21 = 1680,
1/80 = 1 × 21/80 × 21 = 21/1680
Subtract the two like fractions:
2520/1680 - 21/1680 = 2520 - 21/1680 = 2499/1680
After reducing the fraction, the answer is 119/80
In mixed form: 139/80

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