Can you arrange four 9's and use at most 2 math symbols, to make the total 100?

You’re out on the water and see a boat filled with people. You look away for a second and look back again, but this time you don’t see a single person on the boat. Why? Hint: The boat did not sink.

There are two dice with empty faces in front of you and a marker. You can mark any number on each of the faces of the two dice, but you have to display all 31 days of the month using the two of them.

Which numbers will you mark on which dice so that you can easily depict all the dates of the month?

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..:)

When you say goodbye, I am what you need to tie.
I come as a couple and go wherever you run.
Who am I?

The more of this there is, the less you see. What is it?

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

What is at the end of a rainbow?

You have to put a letter on the following to make it a meaningful word. The only challenge is that you can't use 'E'.

S E Q U E N C _

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