Why Aeroplane windows are round?

Why do we preferably have round manhole covers and not square ones?

What number do you get when you multiply all of the numbers on a telephone's number pad?

Using four sevens (7) and a one (1) create the number 100. Except for the five numerals, you can use the usual mathematical operations (+, -, x, :), root and brackets ()

Can you solve the rebus below?

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

An equation has been laid down using a few matchsticks. However, as you can see, the equation is not correct. Can you correct the equation if you are allowed to add or remove 5 matchsticks?

The first two letters signify a male, the first three letters signify a female, the first four letters signify a great, while the entire world signifies a great woman. What is the word?

What can you see in the middle of March and April that you can never see in any other month?

What country can make you shiver?