Pascal cơ bản - thấy vậy chứ không dễ ăn đâu

Program Ca_dao;
Begin
Writeln('Trong dam gi dep bang sen,');
Writeln('La xanh bong trang lai chen nhi vang,');
Writeln('Nhi vang bong trang la xanh.');
Writeln('Gan bun ma chang hoi tanh mui bun');
Readln
End.

Program Phep_Tru;
Var
so1,so2,hieu :Integer;

Begin
Writeln(' CHUONG TRINH THUC HIEN PHEP TRU SO HOC');
Writeln(' co toi da 4 ky so');
Write('-Nhap so thu nhat = ');
Readln(so1);
Write('-Nhap so thu hai = ');
Readln(so2);
hieu:= so1-so2;
Writeln;
Writeln;
Writeln('-------------------------------');
Writeln;
Writeln(' ',so1:4);
Writeln(' - ',so2:4);
Writeln(' -----');
Writeln(' = ',hieu:5);
Readln
End.

Program Cuu_chuong_1;
Var
so :Integer;

Begin
Write('-Bang cuu chuong so may ?: ');
Readln(so);
Writeln;
Writeln;
Writeln(' CHUONG TRINH BANG CUU CHUONG');
Writeln('-------------------------------');
Writeln;
Writeln(so:2,' lan 1 = ',so*1:3);
Writeln(so:2,' lan 2 = ',so*2:3);
Writeln(so:2,' lan 3 = ',so*3:3);
Writeln(so:2,' lan 4 = ',so*4:3);
Writeln(so:2,' lan 5 = ',so*5:3);
Writeln(so:2,' lan 6 = ',so*6:3);
Writeln(so:2,' lan 7 = ',so*7:3);
Writeln(so:2,' lan 8 = ',so*8:3);
Writeln(so:2,' lan 9 = ',so*9:3);
Writeln(so:2,' lan 10 = ',so*10:3);
Readln
End.

Program Cuu_chuong_2;
Var
so,i :Integer;

Begin
Write('-Bang cuu chuong so may ?: ');
Readln(so);
Writeln;
Writeln;
Writeln(' CHUONG TRINH BANG CUU CHUONG');
Writeln('-------------------------------');
Writeln;
For i:=1 To 10 Do
Writeln(so:2,' lan ',i:2,' = ',so*i:3);
Readln
End.

Program Hinh_thang;
Var
a,b,h:Integer;
S:Real;
Begin
Writeln('CHUONG TRINH TINH DIEN TICH HINH THANG');
Write('-Cho biet day ngan = ');
Readln(a);
Write('-Cho biet day dai = ');
Readln(b);
Write('-Cho biet chieu cao = ');
Readln(h);
S := 0.5 * (a + b) * h;
Writeln('+Dien tich hinh thang = ',s:6:2,' met vuong');
Readln
End.