$C1:$
program C1;
uses crt;
var i,S: integer;
Begin
clrscr;
i:=1; S:=1;
while i<30 do
begin
S:=S*i;
i:=i+1;
end;
write('Tich 30 so nguyen duong dau = ',S);
readln
End.
$C2:$
program C2;
uses crt;
var n,i,S; integer;
Begin
clrscr;
write('Nhap n: '); readln(n);
i:=1; S:=1;
while i<=n do
begin
S:=S*i;
i:=i+1;
end;
write(n,'! = ',S);
readln
End.
$C3:$
program C3;
uses crt;
var x,n,i,S: integer;
Begin
clrscr;
write('Nhap x: '); readln(x);
write('Nhap n: '); readln(n);
i:=1; S:=1;
while i<=n do
begin
S:=S*x;
i:=i+1;
end;
write(x,'^',n,' = ',S);
readln
End.
$C4:$
program C4;
uses crt;
var n,i,S: integer;
Begin
clrscr;
write('Nhap n: '); readln(n);
i:=1;
while i<=n do
begin
S:=S+i;
i:=i+1;
end;
write('Tong = ',S);
readln
End.
