bài 1:

uses crt;
var n:integer;
function kt(n:integer):boolean;
var i,s:integer;
begin
s:=0;
for i:=1 to n do
 if n mod i =0 then s:=s+1;
if s=2 then kt:=true else kt:=false;
end;
begin
clrscr;
write('nhap so n:');readln(n);
n:=n+1;
while kt(n)=false do n:=n+1;
write(n);
readln;
end.

bài 2:

uses crt;
var i,j,n: longint;

function ktt(n: longint):longint;
var i,s:longint;
begin
s:=0;
for i:=1 to n-1 do
 if n mod i = 0 then s:=s+i;
ktt:=s;
end;

begin
clrscr;
write('N='); readln(n);
for i:=1 to n do
for j:=1 to n do
 if (ktt(j)=i) and (ktt(i)=j) then writeln(i,'-',j);
readln
end.

bài 3:

uses crt;
var i,j,n,tam,x,k,d:integer;
a:Array[1..100] of integer;
begin
clrscr;
write('nhap so ptu:');readln(n);
for i:=1 to n do
begin
 write('A[',i,']=');
 readln(a[i]);
 if (a[i] mod 2=0) and(a[i] mod 3=0) then d:=d+1;
end;
for i:=1 to n-1 do
for j:=i+1 to n do
 if a[i]>a[j] then
 begin
  tam:=a[i];
  a[i]:=a[j];
  a[j]:=tam;
 end;
for i:=1 to n do write(a[i],' ');
writeln;
writeln(d);
write('nhap so bat ky:');readln(x);
tam:=0;
//chen vao dau mang
if (x<=a[1]) and(tam=0) then
begin
 for i:=n+1 downto 2 do a[i]:=a[i-1];
 a[1]:=x;
 for i:=1 to n+1 do write(a[i],' ');
 tam:=1;
end;
//chen vao cuoi mang
if tam=0 then
 if x>a[n] then
 begin
  a[n+1]:=x;
  for i:=1 to n+1 do write(a[i],' ');
  tam:=1;
 end;
//chem vao giua mang 
if tam=0  then
 begin
  for i:=1 to n do
   if (a[i-1]<=x) and (x<=a[i] )then begin k:=i;break;end;
  for i:=n+1 downto k do a[i]:=a[i-1];
  a[k]:=x;
  for i:=1 to n+1 do write(a[i],' ');
 end;
readln;
end.

1.

uses crt;
var n: longint;
function nt(n: longint): boolean;
var i: longint;
begin
    if n<2 then exit(false);
    for i:=2 to round(sqrt(n)) do if n mod i = 0 then exit(false);
    exit(true);
end;
begin
clrscr;
    readln(n);
    inc(n);
    while not(nt(n)) do inc(n);
    write(n);
    readln
end.

2.

uses crt;
var n,i,j: longint;
function tong(n: longint): longint;
var i: longint;
begin
    tong:=0;
    for i:=1 to n-1 do if n mod i = 0 then tong:=tong+i;
end;
begin
clrscr;
    readln(n);
    for i:=1 to n do for j:=1 to n do if (tong(i)=j) and (i=tong(j)) then writeln(i,'-',j);
    readln
end.

3.

uses crt;
var n,i,j,d,tg,x,k: longint;
    a: array[1..1000001] of longint;
begin
clrscr;
    readln(n);
    d:=0;
    for i:=1 to n do begin
        read(a[i]);
        if (a[i] mod 2 = 0) and (a[i] mod 3 = 0) then d:=d+1;
    end;
    for i:=1 to n do for j:=i+1 to n do if a[i]>a[j] then begin
        tg:=a[i];
        a[i]:=a[j];
        a[j]:=tg;
    end;
    for i:=1 to n do write(a[i],' ');
    writeln;
    writeln(d);
    readln(x);
    if x>a[n] then a[n]:=x
    else for i:=1 to n do if (a[i-1]<=x) and (x<=a[i]) then begin
            k:=i;
            break;
    end;
    a[k]:=x;
    for i:=1 to n do write(a[i],' ');
    readln
end.