Find The Next Number In The Sequence

30 10 15 13 0 16 -15 ?

I am a prime number.
The double of myself is equal to the square of me.

which number am I?

Replace the question mark with the correct number below.

By removing one matchstick and adding one matchstick, can you convert the word "ZOO" to an animal name?

It has five wheels, though often think four, You cannot use it without that one more, You can put things in it, you can strap things on top, You can't find it in the market, but you can still go shop. What is it?

There is a place where if I stand up straight, I will still be considered sideways.

I am a type of word that is spelt incorrectly or used differently, on purpose for humour. What am I?
Hint 1: You can find me in a joke.
Hint 2: I am a play on words.

Two friends were stuck in a cottage. They had nothing to do and thus they started playing cards. Suddenly the power went off and Friend 1 inverted the position of 15 cards in the normal deck of 52 cards and shuffled it. Now he asked Friend 2 to divide the cards into two piles (need not be equal) with equal number of cards facing up. The room was quite dark and Friend 2 could not see the cards. He thinks for a while and then divides the cards in two piles.

On checking, the count of cards facing up is same in both the piles. How could Friend 2 have done it ?

What does this below rebus puzzle mean?

I’m tall when I’m young, and I’m short when I’m old. What am I?