Câu 1:

program Min;
uses crt;
var i,N,S:integer;
begin
   write('Nhap N (N<1001): '); readln(N);
   S:=0;
   for i:=1 to N do if i mod 2 = 1 then S:=S+i;
   write('Tong cac so le tu 1 den ',N,' la: ',S);
   readln
end.

Câu 2:

program Min;
uses crt;
var i,N,S:integer;
begin
   write('Nhap N: '); readln(N);
   S:=0;
   for i:=1 to N do if N mod i = 0 then S:=S+i;
   write('Tong uoc so cua ',N,' la: ',S);
   readln
end.

Câu 3:

program Min;
uses crt;
var A:array[1..3] of integer;
    max,i:integer;
begin
   clrscr;
   write('Nhap 3 so: '); 
   for i:=1 to 3 do readln(A[i]);
   max:=A[1];
   for i:=2 to 3 do if A[i]>max then max:=A[i];
   write('Gia tri lon nhat la: ',max);
   readln
end.

Câu 4: 

program Min;
uses crt;
var A:array[1..4] of integer;
    max,min,i:integer;
begin
   clrscr;
   write('Nhap 4 so: '); 
   for i:=1 to 4 do readln(A[i]);
   max:=A[1]; min:=A[1];
   for i:=2 to 4 do 
   begin
      if A[i]>max then max:=A[i];
      if A[i]<min then min:=A[i];
   end;
   write('Gia tri lon nhat la: ',max);
   write('Gia tri nho nhat la: ',min);
   readln
end.