type
  oper = (plus, minus, mult, divv, eq);

const
  arr: array[1 .. 6] of integer = (7, 12, 24, 6, 6, 4);
  s_ops: array[oper] of char = ('+', '-', '*', '/', '=');
var
  op: set of oper;
  ops: array[1 .. 5] of oper;

procedure calc(level: integer);
var
  i: oper;
  j, left, curr: longint;
begin
  if level = 6 then
  begin
    curr := arr[1];
    for j := 1 to 5 do
      case ops[j] of
        plus: curr := curr + arr[j + 1];
        minus: curr := curr - arr[j + 1];
        mult: curr := curr * arr[j + 1];
        divv: curr := curr div arr[j + 1];
        eq:
        begin
          left := curr; curr := arr[j + 1];
        end;
      end;

    if left = curr then
    begin
      for j := 1 to 5 do
        write(arr[j], ' ', s_ops[ops[j]], ' ');
      writeln(arr[6]);
    end;
  end
  else
    for i := plus to eq do
    begin
      if not (i in op) then
      begin
        include(op, i);
        ops[level] := i;
        calc(level + 1);
        exclude(op, i);
      end;
    end;
end;

begin
  calc(1);
end.

Running "f:\programs\pascal\test.exe"
7 + 12 / 24 = 6 - 6 * 4
7 * 12 - 24 / 6 = 6 + 4