When we see 2 but call 10?

In the attached figure, you can see a chessboard and two rooks placed on the chess board. What you have to find is the number of squares that do not contain the rooks. How many are there?

10+10 and 11+11 can give you the same answer.

Explain how?

Count the number of balls in picture below:

Can you think of a smallest +ve number such that if we shuffle the digits of the number, the new number becomes double the original number?

Look at this sequence from top to bottom. What is the next number in the sequence?
1
11
21
1211
111221
312211

A finger goes in me. You fiddle with me when you're bored. The best man always has me first. What am I?

In a school, there are four subjects. Seventy percent of students study English, seventy five percent of students study Science, eighty five percent of students study Mathematics and eighty percent of students study Spanish.

Can you calculate the percentage of students that study all four subjects?

Can you find out a way through which you can make five squares out of the given figure by moving just six match sticks?

A pond had 60 fish, out of which, all but 20 died.
How many fishes are now present in that pond?