I am a seven-letter word but if you remove four of my letters I will have one left. What word am I?

I am a type of room you cannot enter or leave. Raised from the ground below, I could be poisonous or a delicious treat. What am I?

I go up and I go down.
I go up towards the beautiful sky and down toward the green ground.
I am present tense.
I am past tense too
Children love me.

Who Am I?

In case you were starting to feel confident, this one was meant for third graders in Vietnam. The answer is 66, but we don't blame you for scratching your head about how they got there.

Solve the below puzzle by replacing the question mark with the correct number.

3 6 12

4 8 16

5 10 ?

He runs but never walks. Murmurs, but never talks. Has a bed, but never sleeps. And has a mouth, but never eats?

What do you answer even though it never asks you questions?

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

A donkey is behind another donkey
I'm behind that second donkey
But there is a whole nation behind me

It is a murder you can describe in a word.

You see a mathematical expression in the picture. Can you think of a movie that this expression refers to?