Question: Anthony had 50 pencils. He gave 1/2 of his pencils to Brandon, and he gave 3/5 of the remaining pencils to Charlie. He kept the remaining pencils. How many pencils did Anthony keep?
Solve it. 
Answer: 
Brandon received 50 x 1/2 = 25 pencils
So, there were 50 -25 = 25 pencils left.
Charlie got 25 x 3/5 = 15 pencils.
Thus, Anthony gave away 25 + 15 = 40 pencils.
Therefore, Anthony kept 50 - 40 = 10 pencils.