These brain teasers have been submitted by our visitors from all around the world. These quiz questions are fun for the brain and will puzzle you for some time.

We have lots more puzzles to provide fun for your brain. Have fun solving these quiz questions. Choose from the following brain games:

- Which number should replace the question mark? 1, 4, 7, 7, 10, 13, ?, 19
- How many sides does a pentagon have?
- Which of these numbers are prime numbers: 7, 8, 9, 10, 11, 12, 13, 14?
- This riddle must be done IN YOUR HEAD and NOT using paper and pen or a calculator. Try it!

Take 1000 and add 40 to it. Now add another 1000 to it.

Now add 30. And another 1000.

Now add 20. Now add another 1000. Now add 10.

What is the total? - In a drawer you have black socks and white socks. They are not stored away in pairs. Without looking, how many times will you have to reach into the drawer to come out with a matching pair?
- 10 candles stand burning in a dining room. A strong breeze blows in through an open window and extinguishes 3 of them. Assuming the wind doesn't extinguish any more candles, how many candles do you have left in the end?
- A boy and his big sister are sitting around the kitchen table chatting.

The boy says, "If I take two years away from my age and gave them to you, you'd be twice my age."

The sister added, "Why don't you just give me one more and then I'll be three times you age."

How old are the siblings? - How do you write 23 using only the number 2?

34 using only the number 3?

56 using only the number 5?

100 using only the number 9? - How do you write the number 5 in Roman numerals?
- How many sides does a decagon have?

- What metric unit of length do the letters 'cm' stand for?
- How many squares are there on a chessboard? (Hint: The answer is not 64.)
- If a movie starts in an hour and a half, how many minutes do you have to wait to see it?
- What number is 6 more than 7 x 8?
- Are Roman numerals given in small letters or capital letters?
- What is the next number in this sequence: 2, 5, 9, 14,...
- Add 9 + 1. Then mulitply 9 x 1. Do you get the same answer each time?
- How many sides does an octagon have?
- How many sides does a hexagon have?
- Take a look at all these numbers: 66, 22, 99, 33, 44, 55. What number greater than 1 can be divided into all these numbers without leaving a remainder?

To see more Math Games, click the `Refresh` button, below.