[mak-karpov]

Может так лучше?

Код:

var
 c, r, sum,a: Integer;
begin
  sum := 0;
  sum := Aa[1,1];
  for c := 1 to 20 do
   for r := 1 to 20 do
   begin
      a := Random(aa[c,r]);
      sum := sum + (Aa[c,r] - a)

   end;
   Aa[1,1] := sum;