Subtract 8/21 from 40/90, Solve 40/90

Subtract 8/21 from 40/90

40/90 - 8/21 is 4/63.

Find the least common denominator or LCM of the two denominators:
LCM of 90 and 21 is 630

Next, find the equivalent fraction of both fractional numbers with denominator 630
For the 1st fraction, since 90 × 7 = 630,
40/90 = 40 × 7/90 × 7 = 280/630
Likewise, for the 2nd fraction, since 21 × 30 = 630,
8/21 = 8 × 30/21 × 30 = 240/630
Subtract the two like fractions:
280/630 - 240/630 = 280 - 240/630 = 40/630
After reducing the fraction, the answer is 4/63

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