detemine subtraction result

Hi, suppose I have two matrix A and B as follows:

A =

     1     2     3
     3     3     6
     4     6     8
     4     7     7
B =

     2     2     3
     2     3     6
     4     6     2
     4     7     2

I need the subtraction result of value of A from a particular value say 12 where value of B is 2. i.e 12 minus values of the positions : (1,1) (1,2)(2,1)(3,3)(4,3) are 11, 10,9,4,5 respectively.

is there any easy way to do this?

Answer 1

[Walter Roberson]

12 - A(B==2)

[Mohammad Golam Kibria]

Thnaks