Câu 1:

uses crt;
var n,i,j:longint;
function NT(a:longint):boolean;
var k,dem:longint;
        begin
         dem:=0;
         for k:=1 to a do if(a mod k=0)then inc(dem);
         NT:=dem=2;
        end;
begin
 clrscr;
  readln(n);
  for i:=2 to n do
   for j:=2 to n do
        begin
         if(NT(i))and(NT(j))and(i+j=n)then begin write(i,' ',j); writeln; end;
        end;
 readln;
end.

Câu 2:

uses crt;
var n:string; i,c,max,s:longint; e:integer;
begin
 clrscr;
  readln(n);
  writeln('So nguyen N co ',length(n),' chu so');
  s:=0;
  max:=0;
  for i:=1 to length(n) do
        begin
         val(n[i],c,e);
         s:=s+c;
         if(c>max)then max:=c;
        end;
  writeln('Tong cac chu so cua N la: ',s);
  write('Chu so lon nhat: ', max);
 readln;
end.

bài 1:

uses crt;
var n,i,j: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 exit(true) else exit(false);
end;

begin
clrscr;
write('nhap so n:');readln(n);
for i:=1 to n do
for j:=i to n do
 if (kt(i)) and(kt(j)) and(i+j=n) then writeln(i,' ',j);
readln;
end.

bài 2:

uses crt;
var max,i,a,code,sum:longint;
n:string;
begin
clrscr;
write('nhap so n:');readln(n);
writeln('so nguyen N co ',length(n),' chu so');
max:=0;
for i:=1 to length(n) do
begin
val(n[i],a,code);
sum:=sum+a;
if max<a then max:=a;
end;
writeln('Tong cac cho so cua N la:',sum);
write('chu so lon nhat la:',max);
readln;
end.
readln;
end.