Program SO_NGUYEN_TO;
    Uses crt;
    Var i,n: integer;
   Begin
    Clrscr;

    textcolor (lightgreen+blink);
    Writeln('KIEM TRA SO NGUYEN TO:');

    textcolor (white);
    Writeln('---------------------------------');

    textcolor (lightyellow);
    Write ('Nhap so can kiem tra n = '); readln(n);

    textcolor (white);
    If (n=0) or (n=1) then

        Writeln(n,' Khong phai la so nguyen to')
         Else
        Begin
         i:=1;
         Repeat
          i:= i+1;
         Until (n mod i= 0) or (i*i>n);
         If i*i>n then
          Writeln (n,' la so nguyen to')
         Else
          Writeln (n,' khong phai la so nguyen to');
        End;
    Readln;
   End.

chúc bạn học tốt

program bt;

var

        n,dem,i:integer;

begin

        write('Nhap so can kiem tra: '); readln(n);

        dem:=0;

        for i:=1 to n do if n mod i=0 then dem:=dem+1;

       if dem=2 then write(n,' la so nguyen to') else write(n,' khong la so nguyen to');

       readln;

end.

Bạn có thể cho for i:=2 to n-1 do if n mod i=0 then dem:=dem+1; if dem=0 then write('la so nguyen to') else write('Khong la so nguyen to');

#Chuc_ban_hoc_tot