1 вариант:
Var A,S:integer;
Begin
S:=0;
Write('A = ');ReadLn(A);
S:=S+A;
Write('B = ');ReadLn(A);
S:=S+A;
Write('C = ');ReadLn(A);
S:=S+A;
Write('D = ');ReadLn(A);
S:=S+A;
WriteLn('Sr = ',S/4)
End.
Второй вариант:
Var
A,B,C,D:integer;
Begin
WriteLn('Введите 4 целых числа');
ReadLn(A,B,C,D);
WriteLn('Sr = ',(A+B+C+D)/4)
End.