Can you make four (4) nines (9) equal 100?

They are the five precious gems of an everyday sort and all can be found on a Tennis Court. Who are they?

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 _

I add 5 to 9 and get 2. The answer is correct, so what am I?

What does it mean?

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

There is a box full of marbles,
all but two are blue,
all but two are green,
and all but two are red.

How many marbles are in the box?

Solve this tricky question. You are trapped in a forest. With you, you have a gun preloaded with two bullets in it. In front of you, there is a tiger, a leopard and a jaguar.

How do you survive?

You knock a Table over in the library, and suddenly 20 eyes are looking at you.

People make me, save me, change me, raise me. What am I?