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

A father's child, a mother's child, yet no one's son.

Who am I?

I have four wings but can't fly.
I express no emotions.
I am found on the exact spot every time you look.
I keep toiling away with a little sound.

Do you know what am I?

How much will a 38° angle measure when looked at under a microscope that magnifies ten times?

There is a family that live in a round house. The two parents go out for a movie and leave a babysitter to watch their son. They come back and the kid was not there. Some one kidnapped him. The maid said she was cleaning in a corner. The cook said he was making pizza. The babysitter said she was getting a board game. Who kidnapped him.

Can you name an animal whose killing cannot be performed without spilling your own blood?

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.

If 1+9+8=1, what is 2+8+9?

How many letters are in the alphabet?

Which word is least like the others? Third, fourth, fifth, sixth, seventh, eighth, ninth?