1 không
2
Program UCLN;
uses crt;
var a,b : integer;
begin
write ('nhap so a la ');readln (a);
write ('nhap so b la ');readln (b);
while a < > b do
if a >b then a := a - b else b := b - a ;
write ( ' UCLN la :' , a );
readln
end.
1:
#include <bits/stdc++.h>
using namespace std;
int n,i;
bool kt;
int main()
{
cin>>n;
kt=true;
for (i=2; i*i<=n; i++)
if (n%i==0) kt=false;
if (kt==true && n>1) cout<<"La so nguyen to";
else cout<<"Khong la so nguyen to";
return 0;
}