Câu 1:

uses crt;
var i:integer;
begin
   clrscr;
   for i:=1 to 10 do writeln('Happy Birthday To You');
   readln
end.

Câu 2:

uses crt;
var i:integer;
begin
   clrscr;
   for i:=1 to 10 do write(i:4);
   readln
end.

Câu 3:

uses crt;
var i,a,b:integer;
begin
   clrscr;
   write('Nhap a, b: '); readln(a,b);
   for i:=a to b do write(i:4);
   readln
end.

Câu 4:

uses crt;
var i,a,b,tong:integer;
begin
   clrscr;
   tong:=0;
   write('Nhap a, b: '); readln(a,b);
   for i:=a to b do 
   if i mod 2 = 0 then tong:=tong+i;
   writeln('Tong cac so chan trong day la: ',tong);
   readln
end.

Câu 5:

1/

Program BTH;
uses crt;
var i:longint;
begin
        clrscr;
        For i:=1 to 10 do
                writeln('Happy Birthday to you');
        readln;
end.

2/

Program BTH;
uses crt;
var i:longint;
begin
        clrscr;
        For i:=1 to 10 do
                write(i,' ');
        readln;
end.

3/

Program BTH;
uses crt;
var i,a,b:longint;
begin
        clrscr;
        write('Nhap a: ');readln(a);
        write('Nhap b: ');readln(b);
        For i:=a to b do
                write(i,' ');
        readln;
end.

4/

Program BTH;
uses crt;
var i,a,b:longint;
begin
        clrscr;
        write('Nhap a: ');readln(a);
        write('Nhap b: ');readln(b);
        For i:=a to b do
                If i mod 2=0 then write(i,' ');
        readln;
end.

5/

Program BTH;
uses crt;
var i,a,b,s:longint;
Begin
        clrscr;
        Write('Nhap a: ');readln(a);
        write('Nhap b: ');readln(b);
        For i:=a to b do
                s:=s+i;
        writeln('Tong day so tu ',a,' den ',b,' la: ',s);
        readln;
end.