I have no doors but I have keys, I have no rooms but I have space, you can enter but you can’t leave! What am I?

Prove that twice of ten is the same as twice of eleven.

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

A network of 20 x 10 squares is given to you.

Can you calculate how many unique squares and rectangles can be formed combining two or more individual squares ?

Considering the below equation:

V + II - VI = 10
IV - X + VIII = 20
IV - VII + VI = 30

Then, I + II + III = ?

Women do it once a year after they turn 19 but men get to do it only once in a lifetime. What is it?

Without looking at a calendar, within a minute name, a boy's name using 5 consecutive 1st letters of 5 consecutive months

You are given 16 witch hats. The hats are divided in four different colours – red, blue, green and yellow. Every colour has been assigned to four hats. Now each of the hat will be glued with a label of an arithmetic sign – ‘+’, ‘-‘, ‘x’ or ‘/’. But you can label one sign only once on one colour. In such an arrangement, the hats can be uniquely defined by its colour and symbol.

Can you arrange all the 16 hats in a 4x4 grid in a fashion that no two rows and columns have a repetition of colour or sign?
We have arranged four hats in the below picture to assist you.

Can you count the number of triangles in the given picture?

If you remove one from eleven, it becomes ten. If you remove one from nine, it becomes ten.

How is this possible?