Eight of us go fourth, not back, to protect our king from an attack. What are we?

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

If,
29 - 1 = 30
9 - 1 = 10
14 - 1 = 15

Based on similar logic, Can you prove that the below algebraic equation is true?
11 - 1 = 10 ?

Can you find out the smallest number that can be conveyed as the sum of three squares in three unique ways?

The ages of a father and son add up to 66.
The father's age is the son's age reversed.
How old could they be?
(3 possible solutions).

What does this rebus means ?

PROG WORKRESS

Assume the given figure to be a delicious doughnut. Yes, now you can concentrate more on the puzzle. So you have this delicious doughnut in your refrigerator when your friends come knocking at the door. There are eight of them. Now you have to make three cuts in this doughnut so that each one of you nine people can enjoy a piece of it. Neither you nor your friends would mind the size of their piece as long as they are getting it. How will you do it?

Find the missing number in the sequence below:

What time is it when an elephant sits on a fence?

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