Bài 2: 

Program  bai2;

Uses crt;

Var a,b:real;

Begin

Clrscr;

Write('a='); Readln(a);

Write('b='); Readln(b);

Writeln('Tong cua a va b:',a+b);

Readln

End.

Bài 3:

Program baitap3;

Uses crt;

Begin

Clrscr;

Writeln('So mol cua 50g Na:',50/23:5:2);

Readln

End.

Bài 4:

Program bai4;

Uses crt;

Var a,b:real;

Begin

Clrscr;

Write('a='); Readln(a);

Write('b='); Readln(b);

Writeln('Dien tich hinh A:', (2*a*b)+(a*a*3.14):9:3);

Readln

End.

Bài 5:

Program bai5;

Uses crt;

Var x,y,z:integer;

Begin

Write('Nhap lan luot x va y:');

Readln(x,y);

Writeln('x=',x);

Writeln('y=',y);

z:=x;

x:=y;

y:=z;

Writeln('Sau khi hoan doi:');

Writeln('x=',x);

Writeln('y=',y);

Readln

End.

B2:

uses crt;

var a,b,S:integer;

begin

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

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

S:=a+b;

writeln('Tong 2 so la: ',S);

readln;

end.

B3:

uses crt;

var S:integer;

begin

S:=50/23;

writeln('So mol cua 50g Na la: ',S:5:2);

readln;

end.

B4:

uses crt;

var a,b,S,C:integer;

begin

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

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

S:=a*b;

C:=(a*a*3.14)/2;

writeln('Dien tich  hinh tren la: ',S+C);

readln;

end.

B5:

uses crt;

var x,y,z:integer;

begin

write('nhap x: ');readln(x);

write('nhap y: ');readln(y);

writeln(x,'   ',y);

x:=y;

y:=z;

z:=x;

writeln(x,'   ',y);

readln;

end.