Bill is a good student and a clever boy. He likes to study m_____ , and he can do all of the math problems in his book easily. One day on his way to school, Bill walks p___ a fruit shop. There is a s_____ in the window. It says , ―Apple－six for 5 cents(美分). He has an i____ and he goes into the shop. “ How m_______ are the apples?” He asks the shopkeeper.  “Six for 5 cents.”  “But I don’t want six apples. ”“How many apples do you want? ” “It is not a q___ of how many apples I want. It is a math problem.” “What is your math problem? Can you tell me? ”asks the man.  “Well, if six apples cost 5 cents, then five apples cost 4 cents, four apples cost 3 cents, three apples cost 2 cents, two apples cost 1 cent and one apple costs n____. I only want one apple.” Bill g_____ a good apple and begins to eat it, then he is h______ to walk out of the shop. The man looks at the young boy in surprise(惊讶地) and doesn’t know w______to say.