Which is the smallest number that you can write using all the vowels exactly once?

What is the below Rebus indicate?

No matter how little or how much you use me, you change me every month. What am I?

I look at you, you look at me I raise my right, you raise your left. What am I?

There are people and strange monkeys on this island, and you can not tell who is who (Edit: until you understand what they said - see below). They speak either only the truth or only lies.
Who are the following two guys?
A: B is a lying monkey. I am human.
B: A is telling the truth.

Can you identify the hidden rebus in the image below?

What is the fastest way to double your money?

If eleven plus two equals one, what does nine plus five equal?

I have one of the three numbers: 1, 2, or 3 in my mind. I speak only truth. You can ask me just one question for which I will only reply in yes or no or don't know. What question will you ask from me so that you are able to know the number?

Why is the Hole below a Lock?