Consider the example:

#include <stdio.h>

#define CALC(X,Y) (X*Y)

int main()
{ 
	printf("%d\n",CALC(1+2, 3+4));
	return 0;
}

Output

11

Explanation:

If you are thinking that 1+2 and 3+4 will be evaluated before the expansion and it will be expanded as 3*7 then, you are wrong.

The arguments evaluate after the call, thus Macro CALC(1+2,3+4) will be expanded as = (1+2*3+4) = (1+6+4) =(11).

Finally, the output will be 11.