Evaluate
-\frac{31}{78}\approx -0.397435897
Factor
-\frac{31}{78} = -0.3974358974358974
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\frac{8}{78}-\frac{39}{78}
Least common multiple of 39 and 2 is 78. Convert \frac{4}{39} and \frac{1}{2} to fractions with denominator 78.
\frac{8-39}{78}
Since \frac{8}{78} and \frac{39}{78} have the same denominator, subtract them by subtracting their numerators.
-\frac{31}{78}
Subtract 39 from 8 to get -31.
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