Subtract 21/90 from 28/7, Solve 4 0/7

Subtract 21/90 from 28/7

1^st number: 4 0/7, 2^nd number: 21/90

28/7 - 21/90 is 113/30.

Find the least common denominator or LCM of the two denominators:
LCM of 7 and 90 is 630

Next, find the equivalent fraction of both fractional numbers with denominator 630
For the 1st fraction, since 7 × 90 = 630,
28/7 = 28 × 90/7 × 90 = 2520/630
Likewise, for the 2nd fraction, since 90 × 7 = 630,
21/90 = 21 × 7/90 × 7 = 147/630
Subtract the two like fractions:
2520/630 - 147/630 = 2520 - 147/630 = 2373/630
After reducing the fraction, the answer is 113/30
In mixed form: 323/30

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