The centre of the third figure is empty. What digit should fit inside?

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

Different lights make me strange by changing me into different sizes. What am I?

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

Bopanna was working on a murder case when he received a message about the location of the murder weapon.
The message was encrypted as below.

"deb mitciv eht edisni neddih si nopaew redrum ehT"

Tell me the location of the murder weapon.

Mr. Buttons was all set to go to the village of Buttonland to meet his friend. So, he packed his bags and left for the village at 5 in the morning. Upon travelling on a road for miles, he came across a point where the road diverged into two. He was confused on which road to take. He gazed around and he saw two owls sitting on a branch. He thought he could ask for directions for the village from the two owls. So he went to the tree. There he saw a sign which read, "One owl always lies, and one is always truthful. They both fly away if you ask them more than 1 question."
Mr. Buttons was caught in the dilemma of what to ask? And from which owl to ask, since he only had one question. What should Mr. Buttons ask?

You throw me out when you want to use me and you take me in when you don't want to use me.

Who Am I?

You need to remove two matchsticks to make the below equation true. Can you do it ?

Can you identify the hidden rebus in the image below?

What is the coolest letter in the alphabet?