Can you make a six-letter word using the letters N, A and B ?

Move three sticks of the spiral below to form a square.

13 decks of cards have been mixed. What is the minimum number of cards that must be taken out from the above-mixed cards to guarantee at least one 'four of a kind?

If,

A = 1

B = 2

C = 3

...

...

Z = 26.

Based on above rule, you need to find an eleven letter word whose letter sum is equal to 52.

You are given four results as below:
1111 = F
2222 = E
3333 = T
Then, can you find out how to code 4444?

The person who makes it has no need for it; the person who buys it has no use for it. The person who uses it can neither see nor feel it. What is it?

I have an eye but still cannot see.

Who am I?

In the given figure, you can see that four match sticks are used to form a square. Can you form five squares by using six matches?

Can you solve this amazing hard number series problem?
7, 8, 10, 12, 16, 18 ?

I was born in a small house and I live in it all alone. No windows and no doors have been assigned to my house. The only way I can go out is by breaking through the walls of my house.

Who am I?