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;

}

program TinhTongVaUoc;

var
  a, b, sum, i: integer;
  uoc: boolean;

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

  write('Nhap so b: ');
  readln(b);

  // Tinh tong a+b
  sum := a + b;
  writeln('Tong cua a va b la: ', sum);

  // In ra cac uoc cua tong
  write('Cac uoc cua tong a+b la: ');
  for i := 1 to sum do
  begin
    if sum mod i = 0 then
      write(i, ' ');
  end;
  writeln;

  // Kiem tra xem tong a+b co phai la so hoan hao hay khong
  uoc := false;
  for i := 1 to sum - 1 do
  begin
    if sum mod i = 0 then
      uoc := true;
  end;
  if uoc and (sum = 2 * sum div 2) then
    writeln('Tong a+b la so hoan hao')
  else
    writeln('Tong a+b khong phai la so hoan hao');
end.

program TinhTongVaUocSo;
var
  a, b, tong, i: integer;
  laSoNguyenTo: boolean;
begin
  write('Nhap a: ');
  readln(a);
  write('Nhap b: ');
  readln(b);
  tong := a + b;
  writeln('Tong cua a va b la: ', tong);
  writeln('Uoc so cua tong la:');
  for i := 1 to tong do
  begin
    if tong mod i = 0 then
      writeln(i);
  end;
  laSoNguyenTo := true;
  if tong < 2 then
    laSoNguyenTo := false
  else
    for i := 2 to trunc(sqrt(tong)) do
      if tong mod i = 0 then
      begin
        laSoNguyenTo := false;
        break;
      end;
  if laSoNguyenTo then
    writeln('Tong a va b la so nguyen to')
  else
    writeln('Tong a va b khong phai la so nguyen to');
  readln;
end.

program TinhTongVaUocCuaTong;

var a, b, tong, i: integer;
     SoNguyenTo: boolean;

begin
writeln('Nhap vao hai so a va b (a > 0, b > 0): ');
  write('a = ');
  readln(a);
  write('b = ');
  readln(b);
  tong := a + b;
  writeln('Tong cua a + b = ', tong);
  writeln('Uoc cua tong a + b: ');
  for i := 1 to tong do
  begin
    if tong mod i = 0 then
      writeln(i);
  end;
  SoNguyenTo := true;
  if tong < 2 then
  SoNguyenTo := false
  else
    for i := 2 to trunc(sqrt(tong)) do
    begin

  if tong mod i = 0 then
 begin
 SoNguyenTo := false;
        break;
      end;
    end;
   if SoNguyenTo then
    writeln('Tong a + b la so nguyen to:')
  else
    writeln('Tong a + b khong phai la so nguyen to:');
  end.

uses crt;

var a,b,ucln,bcnn,i:integer;

begin

clrscr;

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

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

ucln:=1;

if a<b then begin

                        for i:=1 to a do

                           if (a mod i=0) and (b mod i=0) then                                             begin

                                     if ucln<i then ucln:=i;            

                               end;    

                   end else begin

              for i:=1 to b do

                  if (a mod i=0) and (b mod i=0) then

                      begin

                           if ucln<i then ucln:=i;

                      end;      

       end;

bcnn:=a*b;

for i:=a*b-1 downto 1 do  

   if (i mod a=0) and (i mod b=0) then      

       begin

             if bcnn>i then bcnn:=i;      

       end;

writeln('Uoc chung lon nhat la: ',ucln); 

writeln('Boi chung nho nhat la: ',bcnn);

readln;

end.

1: VCT pascal kiểm tra số n có phải là số nguyên tố không

uses crt;

var n,i,kt:integer;

begin

clrscr;

repeat

write('nhap n='); readln(n);

if n<=1 then writeln('ban da nhap sai,yeu cau ban nhap lai');

until n>1;

kt:=0;

for i:=2 to n-1 do

if n mod i=0 then

begin

kt:=1;

break;

end;

if kt=0 then writeln(n,' la so nguyen to')

else writeln(n,' khong la so nguyen to');

readln;

end.

2:VCT pascal kiểm tra số n có phải là số hoàn hảo không

uses crt;
var n,i,t:integer;
begin
clrscr;
write('nhap n:'); readln(n);
t:=0;
for i:=1 to n-1 do
if n mod i=0 then begin
t:=t+i;
end;
if t=n then writeln(n,' la so hoan hao')
else write(n,' khong la so hoan hao');
readln;
end.

3:VCT pascal kiểm tra số n xuất ra màn hình các số nguyên tố từ 2 đến n

uses crt;
var n,i,kt,j:integer;
begin
clrscr;
repeat
write('nhap n='); readln(n);
if n<=2 then writeln('ban da nhap sai, yeu cau ban nhap lai');
until n>2;
writeln('day cac so nguyen to trong khoang tu 2 toi ',n,' la:');
for i:=2 to n do
begin
kt:=0;
for j:=2 to i-1 do
if i mod j=0 then kt:=1;
if kt=0 then write(i:4);
end;
readln;
end.

1:

program b1;

ues crt;

var i,n,dem:longint;

procedure nhap(var n:longint);

begin

write('n=');readln(n);

end;

function NT(b:longint):boolean;

var dem,i:longint;

uses crt;
var n,i,t:integer;
begin
clrscr;
write('nhap n:'); readln(n);
t:=0;
for i:=1 to n-1 do
if n mod i=0 then begin
t:=t+i;
end;
if t=n then writeln(n,' la so hoan hao')
else write(n,' khong la so hoan hao');
readln;
end.