Can you find the missing piece of the Porsche?

Name a key which is hardest to turn.

My cousin lives in one story house in Antarctica. His house is made the of-of sandstone. what is the color of stairs?

I am something people love or hate. I change peoples appearances and thoughts. If a person takes care of them self I will go up even higher. To some people I will fool them. To others I am a mystery. Some people might want to try and hide me but I will show. No matter how hard people try I will Never go down. What am I?

Find The Next Number in the series:

12 13 15 17 111 113 117 119 123 ?

Can you find the odd number in the following five choices?

1) 482636
2) 259807
3) 865195
4) 104739
5) 391744

There are 20 people in an empty, square room. Each person has full sight of the entire room and everyone in it without turning his head or body, or moving in any way (other than the eyes). Where can you place an apple so that all but one person can see it?

Which Number is the odd one out?

A) 7145
B) 2716
C) 5321
D) 4135

What does this Rebus Picture mean?

I am a prime number.
The double of myself is equal to the square of me.

which number am I?