What is the riddle which can be asked all day with a different correct answer each time.

An equation has been laid down using a few matchsticks. However, as you can see, the equation is not correct. Can you correct the equation if you are allowed to add or remove 5 matchsticks?

If we add four times the age of John four years from now to five times his age five years from now we get ten times his current age.

How old will John be two years from now?

You have 10 balls with you. A friend of yours out of nowhere asks you to place those ten balls in five lines such that each of the lines has exactly 4 balls on them. He needs to check your intelligence. Prove him by doing the task.

In a mathematical quiz, you are asked the following question:

Use three 9s in a mathematical expression without dividing or multiplying to form the number one.

Can you answer the question?

I can be cracked, made, told, and played. What am I?

It walks on 4 when its young, walks on 2 when it's older, and walks on 3 when its very old?

A word I know,
Six letters contain,
Subtract just one,
And twelve is what remains.

I have holes on the top and bottom. I have holes on my left and on my right. And I have holes in the middle, yet I still hold water. What am I?

I have an eye but still cannot see.

Who am I?