Subtract 10/80 from 63/42, Solve 1 21/42

Subtract 10/80 from 63/42

1^st number: 1 21/42, 2^nd number: 10/80

63/42 - 10/80 is 11/8.

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,
10/80 = 10 × 21/80 × 21 = 210/1680
Subtract the two like fractions:
2520/1680 - 210/1680 = 2520 - 210/1680 = 2310/1680
After reducing the fraction, the answer is 11/8
In mixed form: 13/8

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