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?

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

I go up and I go down.
I go up towards the beautiful sky and down toward the green ground.
I am present tense.
I am past tense too
Children love me.

Who Am I?

Jack was having a candle light dinner with his girlfriend. Suddenly a cold gush of wind entered through the open window and three of the ten candles were extinguished. Assuming that none of the other candles were extinguished.

How many candles are they left with in the end ?

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

I was speeding and ran through a stop sign, yet two traffic officers who were there do nothing about it.

why?

A shepherd had 18 sheep, out of which, all but ten died.

Can you tell us how many sheep was he left with?

Which flower has two lips?

How many times can you subtract the number two from the number fifty?

Below, you will find the mathematical proof that 10 equals 9.99999?. But is that possible or there is something wrong about it? Can you find the error?

x = 9.999999...
10x = 99.999999...
10x - x = 90
9x = 90
x = 10