Can you convert the number zero(0) into a positive number using just one mathematical operator ?

Can you make the below equation true by using any three numbers from "1, 3, 5, 7, 9, 11, 13 and 15"?

( ) + ( ) + ( ) = 30

In the figure, you can see nine stars. What you have to do is connect all of them by using just four line and without lifting your hand i.e. in a continuous flow.

I am dry when I go inside, but wet when I am pulled outside.
The longer I am inside, the stronger I get
When I am completely out, I am wet and I literally sag
Who am I?

This puzzle is for Harry Potter fans. Do you know why Tom Riddle is called Lord Voldemort?

When my father was 31 I was 8. Now he is twice as old as me. How old am I?

What 4-letter word can be written forward, backward or upside down, and can still be read from left to right?

Using eight eights and addition only, can you make 1000?

Can you find the six hidden animals in the picture below?

Can anyone tell me a word in the English dictionary which has a silent 'z'?