VD1:

Program vd1;

Uses crt;

Var a,b: integer;

Begin

Clrscr;

Write('nhap so nguyen a:'); readln(a);

Write('nhap so nguyen b:'); readln(b);

Writeln('Tong 2 so nguyen la:',a+b);

Readln;

End.

VD2:

Program vd2;

Uses crt;

Var r: integer;

      C:real;

Const pi=3.14;

Begin 

Clrscr;

Write('Nhap ban kinh cua duong tron:'); readln(r);

C:=2*pi*r;

Writeln('Chu vi cua duong tron do la:', C);

Readln

End.

VD3:

Program vd3;

Uses crt;

Var a,b,c:integer;

      T,x1,x2:real;

Begin

Clrscr;

write('Nhap lan luot so a, b, c='); readln(a,b,c);

T:=b*b-4*a*c;

If T<0 then writeln('Phuong trinh vo nghiem')

else if T=0 then

     Begin

      x1:=-b/(2*a);

      Writeln('Phuong trinh co nghiem kep', x1);

      End else

      Begin

      x1:=(-b+sqrt(D))/(2*a);

      x2:=(-b-sqrt(D))/(2*a);

      Writeln('Phuong trinh co 2 nghiem phan biet', x1 ,'   ' ,x2);

Readln

End.

vd1

program tinh_tong;

uses crt;

var a, b, c: integer;

begin

clrscr;

write('Nhap a: '); readln(a);

write('Nhap b: '); readln(b);

c:=a+b;

write('Tong 2 so nguyen a, b la: ', c);

readln

end.

vd2

Program chuvi;

Uses Crt;

Var r,cv:real;

Begin

Clrscr;

Write ('Nhap ban kinh r=');

readln(r);

cv:=2*3.14*r;

Writeln('Chu vi hinh tron la:',cv:6:2);

Readln;

End.

vd3

Program giai_phuong_trinh_bac_2;
Uses crt;
Var a,b,c,x1,x2,x,DT:Real;
BEGIN
CLRSCR;
Write('a= '); Readln(a);
Write('b= '); Readln(b);
Write('c= '); Readln(c);
DT:=b*b - 4*a*c;
If DT>0 then
Begin
Writeln('Phuong trinh co 2 nghiem phan biet la');
x1:= (-b+SQRT(DT))/(2*a);
x2:= (-b-SQRT(DT))/(2*a);
Writeln('x1= ', x1:8:2);
Writeln('x2= ', x2:8:2);
End
Else
If DT=0 Then
Begin
Writeln('Phương trinh co 1 nghiem kep la');
x:=(-b/(2*a));
Writeln('x= ', x:8:2);
End
Else
Writeln(' Phương trinh vo nghiem');

Readln;
END.