p = 1; N = 3; B = 3; R = 5; Q = 9;

but,

 Q = R + R    =>   9 = 5+5 => 9 =10

 Q = B+B+N  =>   9 = 3+3+3 => 9=9

 Q = R+B      =>   9 = 5+3    => 9=8

 R = B+P+P   =>   5 = 3+1+1 => 5=5

 R+P+P = B+N => 7=6

 R+R = B+B+N => 10=9

So chess is not mathematics . Then why it is tough?

does it have to have 5+5=10 to make it tough?  does it need math to make it tough?  I'm confused as to the point of your question.

Your logic is false. Two rooks are worth more than a queen. Your equation proved that but you chose not to believe it.

Now thirty people are going to post telling you how the values of the pieces changes with the position on the board.

Chess is not mathematics, but it does *involve* mathematics.  It is tough because it requires constant calculation, evaluation, and re-evaluation.  And I will be person #1 of 30 to state that the values of the pieces are constantly changing (e.g. a pawn marching down the board).

i haven't created those equation. I got those values through online sources and books . I Know value depends on position. Like N is powerful than B in closed center game, while open posiotion favours B.

THATS WHY I SAID "CHESS NOT MATHS"

LOL ...and I'll volunteer to be #2. Knights and bishops change values all the time depending on their location and the pawn structure.

.

revoked

If you know value depends on position why do you use (erroneous) equations that totally ignore position?

I believe Soltis, Kaufman and a few other GMs re-valued the pieces based on statistical analysis of millions of recorded games.

The following article will help you understand the nuances of "actual material imbalances" rather than simple value-assignment.  The numbers you quoted are usually a way for beginners to maintain a track of material.  Once you start getting better, many a piece's value becomes extraordinarily dynamic.

http://home.comcast.net/~danheisman/Articles/evaluation_of_material_imbalance.htm

I would think that chess is pure mathematics, but we will never figure out the true equations of a position...