The information's given in the question should be very minutely checked. Based on those given information's the answer to the question can easily be deduced.
Amount of sugar in the cabinet of Cassie = 1/2 pound
Amount of sugar required by Cassie to make her cake recipe = 2/10 pound
= 1/5 pounds
Then
The number of cakes that Cassie can make = (1/2)/(1/5)
= 5/2
= 2 1/2
So from the above deduction we can easily conclude that Cassie can make a total of 2 cakes with the sugar she has and there will still be some sugar left.