You received 1⁄3 pound of candy from your grandmother, 1⁄2 pound of candy from your sister, but your best friend ate 1⁄5 pound of candy. How much candy do you have left?

Give them the same denominator.

19/30 is what you have left

You set the same denominator which would become

2/6 and 3/6

5/6 is how much chocolate you get

Now you set the same denominator again

50/60 and 12/60

subtraction would cause

38/60 is amount of candy left

simplify to 19/30