Subtract 9/21 from 90/40, Solve 2 10/40

Subtract 9/21 from 90/40

1^st number: 2 10/40, 2^nd number: 9/21

90/40 - 9/21 is 51/28.

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,
90/40 = 90 × 21/40 × 21 = 1890/840
Likewise, for the 2nd fraction, since 21 × 40 = 840,
9/21 = 9 × 40/21 × 40 = 360/840
Subtract the two like fractions:
1890/840 - 360/840 = 1890 - 360/840 = 1530/840
After reducing the fraction, the answer is 51/28
In mixed form: 123/28

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