Easy logic riddles for teens with simple answers

Think of a number. Double it. Add ten. Half it. Take away the number you started with. What is your number?

What kinds of stones are never found in the ocean?

I dig out tiny caves, and store gold and silver in them. I also build bridges of silver and make crowns of gold. They are the smallest you could imagine. Sooner or later everybody needs my help, yet many people are afraid to let me help them. What am I?

Tom's height is six feet, he is an assistant at a butcher's shop, and wears size 12 shoes. What does he weigh?

I have a face but no eyes, hands but no arms. What am I?

It is greater than god, more evil than the devil, the poor have it, the rich need it, and if you eat it, you will die? What is it?

Our dinner guests cry that we are evil, when they notice their place in the meal. But its no big deal why; we are just one big happy tribe! And we get really fed up with people! Who, What or Are we?

It is impossible to keep it until you give it someone else. What is that?

What is so delicate that saying its name breaks it?

I am not alive but I grow. I don't have lungs but I need air. What am I?