If "P" means "-", "Q" means "/", "R" means "+", and "S" means "*" then find the value of the following:

21 Q 7 R 9 S 10 P 13

You are given a cube that is made with the help of 10x10x10 smaller cubes summing up to a total of 1000 smaller cubes. You are asked to take off one layer of the cubes.
How many remain now?

When I go in I might cause pain. I cause you to spit and ask you not to swallow. I can fill your hole. What am I?

As shown in the image, the nine Dogs are square fenced. By constructing just two square fences can you make sure that two Dogs cannot meet each other without crossing the fence?

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

Can you make a six-letter word using the letters N, A and B ?

The square root of number 121 is "11". What is the square root of the number "12345678987654321."?

Get total of 120 by using five zeros 0,0,0,0,0 and any one mathematical operator.
Do you ?

What does the following represent?

N N N N N N N

A A A A A A A

C C C C C C C

I am the one who remains awake when you sleep. But I need to rest when you awake. Who Am I?