Subtract 75/40 from 70/42, Solve 1 28/42

Subtract 75/40 from 70/42

1^st number: 1 28/42, 2^nd number: 1 35/40

70/42 - 75/40 is -5/24.

Find the least common denominator or LCM of the two denominators:
LCM of 42 and 40 is 840

Next, find the equivalent fraction of both fractional numbers with denominator 840
For the 1st fraction, since 42 × 20 = 840,
70/42 = 70 × 20/42 × 20 = 1400/840
Likewise, for the 2nd fraction, since 40 × 21 = 840,
75/40 = 75 × 21/40 × 21 = 1575/840
Subtract the two like fractions:
1400/840 - 1575/840 = 1400 - 1575/840 = -175/840
After reducing the fraction, the answer is -5/24

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