(1/3) + (-5/6) + (-1/2)

Find a common denominator for these three fractions; try 6

Now, take (1/3);

3 goes into 6 two times, multiplied by the numerator = (2/6)

Now (-5/6); 6 goes into 6 one time, multiplied by the numerator = -5/6 (obviously)

And finally, (-1/2); 2 goes into 6 three times, multiplied by -1 = -3/6

Now, we have (2/6) + (-5/6) + (-3/6)

= (2/6) - (5/6) - (3/6)

(2 - 5 - 3)/6 = -6/6 =-1