Subtract 7/80 from 28/21, Solve 1 7/21

Subtract 7/80 from 28/21

1^st number: 1 7/21, 2^nd number: 7/80

28/21 - 7/80 is 299/240.

Find the least common denominator or LCM of the two denominators:
LCM of 21 and 80 is 1680

Next, find the equivalent fraction of both fractional numbers with denominator 1680
For the 1st fraction, since 21 × 80 = 1680,
28/21 = 28 × 80/21 × 80 = 2240/1680
Likewise, for the 2nd fraction, since 80 × 21 = 1680,
7/80 = 7 × 21/80 × 21 = 147/1680
Subtract the two like fractions:
2240/1680 - 147/1680 = 2240 - 147/1680 = 2093/1680
After reducing the fraction, the answer is 299/240
In mixed form: 159/240

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