Why Aeroplane windows are round?

Using Only Five 5's and any mathematical operator make sum as 37

How many points are there on the globe where, by walking one mile south, then one mile east and then one mile north, you would reach the place where you started?

Find out a multi-digit number that if multiplied by the number 9 or any of its multiplications products (i.e. 18, 27, 36, 45,..) will result in the multiplication factor repeated (n) number of times.

What 4-letter word can be written forward, backward or upside down, and can still be read from left to right?

There is a number which when you multiply by 3 and subtract 2 from the result, then the resulting number is the reverse of the actual number.

What is the smallest number that stands true on the statement?

That attorney is my brother, testified the accountant.

But the attorney testified he didn't have a brother.

Who is lying?

A four-digit number (not beginning with 0) can be represented by ABCD. There is one number such that ABCD=A^B*C^D, where A^B means A raised to the B power. Can you find it?

What English word has three consecutive double letters?

By moving exactly three matchsticks can you make the below equation true.It can be solved by 3 ways.