Why do people go to bed?

I have feet, but no legs. Which animal Am I?

Christina, Allison and Lena are 3 daughters of John a well-known Mathematician, When I asked John the age of their daughters. He replied "The current age of her daughters is prime. Also, the difference between their ages is also prime."

How old are the daughters?

When I got four, I have it none.
When I got two, I have it some.
When I got none, I have it all.

What is it?

A blonde put eyeliner on her head. Why?

How can you make number one disappear by adding something to it?

People put me on the table and cut me but do not eat me. What am I?

What is the largest number you can write with just 3 digits?

A Man gave one of his sons 10 cents and another son was given 15 cents. What time is it?
Hint: Figure out the relation between time and number, is not so easy..:)

Can you move 2 matchsticks to form four equal sized squares.