What has many keys but can’t open a single lock?

What do you call two witches who live together?

77x = 189x = 345x 
¿Which is the x value?

Everyone has it and no one can lose it?

You are my brother, but I am not your brother. Who am I?

There are 10 fish in a fish tank: 
- 2 are drowned. 
- 4 swim far away. 
- 3 die. 
How many fish are left?

I am always in front and never behind. 
What am I?

What did the wall say to the calendar ?

What is as big as you are and yet does not weigh  anything?

What gets wet as it dries?

It is something you will never see again.

What doesn't ask questions, but need to be answered?