If you say my name, I will no longer exist. What am I?

Can you find out what is missing?

1 3 5
2 4 ?

Hint: It's not six. Think out of the box.

What is more useful when it is broken?

Move four matchsticks to the below square to form three squares?

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

which number am I?

What is the fastest way to double your money?

What do you get if you add 2 to 100 four times?

The Puzzle: A girl, a boy, and a dog start walking down a road.

They start at the same time, from the same point, in the same direction.

The boy walks at 5 km/h, the girl at 6 km/h.

The dog runs from boy to girl and back again with a constant speed of 10 km/h. The dog does not slow down on the turn.
How far does the dog travel in 1 hour?

What word is pronounced the same if you take away four of its five letters?

If an earthquake is 1 point higher on the Richter Scale than another earthquake which is actually 10 times stronger, how much stronger would an earthquake be if it was just half a point higher on the Richter scale?