Good Riddles

Question: A child asked his grandfather: "When you were young, what were you?" The grandfather replied, "I am one hundred, nothing, one thousand, one and one hundred". What's his career?

Question: I am a 3 letter word spelled with 3 different letters, and if you reverse the spelling of the word, it will sound the same. What word am I?

Question: A cat,mouse,and dog all had an instrument,the dog had a flute,the cat had a trombone and the mouse's instrument bugs the dog.What was the mouse's instrument?

Question: Without me you're blind but once you touched in the right place you can turn me on. What am I?

Question: Bobby's teacher gave him a math quiz. Every time he got an answer right, points would be taken away, so whoever had the most points, got the most questions wrong. Bobby's score was the highest, yet he still got the most questions correct out of the class. How is this possible?