question: Dean has 30 marbles. He gives 1/5  of them to Jamie and gives 10 to Donald. How many marbles are left for Dean?
answer: Dean gives 30 x 1/5 = <<30*1/5=6>>6 marbles to Jamie.
  He gives a total of 6 + 10 = <<6+10=16>>16 marbles in all.
  So, Dean has 30 - 16 = <<30-16=14>>14 marbles left.
  #### 14