Subtract 21/54 from 42/70, Solve 42/70

Subtract 21/54 from 42/70

42/70 - 21/54 is 19/90.

Find the least common denominator or LCM of the two denominators:
LCM of 70 and 54 is 1890

Next, find the equivalent fraction of both fractional numbers with denominator 1890
For the 1st fraction, since 70 × 27 = 1890,
42/70 = 42 × 27/70 × 27 = 1134/1890
Likewise, for the 2nd fraction, since 54 × 35 = 1890,
21/54 = 21 × 35/54 × 35 = 735/1890
Subtract the two like fractions:
1134/1890 - 735/1890 = 1134 - 735/1890 = 399/1890
After reducing the fraction, the answer is 19/90

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