# 11 Good Math Riddles

By: Justin Zablocki (author, Zablocki Bros. LLC) on September 4th, 2013 12:00 AM.

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Math and riddles go perfectly together because they are both children of logic. Math riddles combine mathematical theory and techniques with classic word riddles to make a fun and tricky new riddle. These riddles are organized easiest to hardest. How many and how fast can you solve them?

1. There are 11 bananas and you take 4, how many do you have?

2. You have 2 coins that add up to 35 cents. One of the coins is not a quarter.

What kind of coins do you have?

3. How can you add 8 8's to make 1000?

4. What number do you get when you multiply all of the numbers on a telephone's number pad?

5. On a clock, how many times a day do the minute and hour hand overlap?

6. If you have an 11 minute and 13 minute hourglass, how can you accurately time 15 minutes?

7. There are 100 coins scattered in a dark room. 90 have heads facing up and 10 are facing tails up. You cannot tell which coins are which. How do you sort the coins into two piles that contain the same number of tails up coins?

8. There is a chain nailed to the wall. The chain is 10 feet long and the center of the chain dips down 5 feet from where each side of the chain is nailed to the wall. How far are the 2 ends of chain from each other?

9. You have a glass of water that looks about half full. How can you tell, only using the glass of water itself, if the glass is half full or not?

The glass is a right cylinder.