Subtract 21/35 from 21/45, Solve 21/45

Subtract 21/35 from 21/45

21/45 - 21/35 is -2/15.

Find the least common denominator or LCM of the two denominators:
LCM of 45 and 35 is 315

Next, find the equivalent fraction of both fractional numbers with denominator 315
For the 1st fraction, since 45 × 7 = 315,
21/45 = 21 × 7/45 × 7 = 147/315
Likewise, for the 2nd fraction, since 35 × 9 = 315,
21/35 = 21 × 9/35 × 9 = 189/315
Subtract the two like fractions:
147/315 - 189/315 = 147 - 189/315 = -42/315
After reducing the fraction, the answer is -2/15

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