Subtract 25/21 from 10/40, Solve 10/40

Subtract 25/21 from 10/40

1^st number: 10/40, 2^nd number: 1 4/21

10/40 - 25/21 is -79/84.

Find the least common denominator or LCM of the two denominators:
LCM of 40 and 21 is 840

Next, find the equivalent fraction of both fractional numbers with denominator 840
For the 1st fraction, since 40 × 21 = 840,
10/40 = 10 × 21/40 × 21 = 210/840
Likewise, for the 2nd fraction, since 21 × 40 = 840,
25/21 = 25 × 40/21 × 40 = 1000/840
Subtract the two like fractions:
210/840 - 1000/840 = 210 - 1000/840 = -790/840
After reducing the fraction, the answer is -79/84

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