Find The Next Number In The Sequence

30 10 15 13 0 16 -15 ?

A seven-year-old kid challenged his classmates that he can make the number one disappear by adding something to it.

How can he do that?

He digs out tiny caves and stores gold and silver in them. He also built bridges of silver and made crowns of gold. They are the smallest you could imagine. Sooner or later everybody needs his help, yet many people are afraid to let him help them. Who is he?

I make two people out of one. What am I?

It is always ahead of me yet I can never see it. What is it?

It's a test that will check your IQ.

Suppose you have one 11 minute hourglass and one 13 minute hourglass.

Can you measure exactly fifteen minutes using them ?

Can you find out the missing number?

? 4 5 3 5

9 5 7 10 3

what does this picture(rebus) riddle means ?

A finger goes in me. You fiddle with me when you're bored. The best man always has me first. What am I?

What does this rebus puzzle means ?