Subtract 30/4 from 21/70, Solve 21/70

Subtract 30/4 from 21/70

1^st number: 21/70, 2^nd number: 7 2/4

21/70 - 30/4 is -36/5.

Find the least common denominator or LCM of the two denominators:
LCM of 70 and 4 is 140

Next, find the equivalent fraction of both fractional numbers with denominator 140
For the 1st fraction, since 70 × 2 = 140,
21/70 = 21 × 2/70 × 2 = 42/140
Likewise, for the 2nd fraction, since 4 × 35 = 140,
30/4 = 30 × 35/4 × 35 = 1050/140
Subtract the two like fractions:
42/140 - 1050/140 = 42 - 1050/140 = -1008/140
After reducing the fraction, the answer is -36/5

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