bài 3

uses crt;
var s,tmp:string;
begin
clrscr;
    readln(s);

    if(length(s) = 10) then 
        begin
            tmp:=copy(s, 1, 3);
            if(tmp = '096') or (tmp = '097') or (tmp = '098') then
                writeln('Thuoc mang Viettel')
            else writeln('Khong thuoc mang Viettel');
        end
    else if(length(s) = 11) then 
        begin
            tmp:=copy(s, 1, 4);
            if(tmp = '0162') or (tmp = '0163') or (tmp = '0164')
                or (tmp = '0165') or (tmp = '0166') or (tmp = '0167') or (tmp = '0168')
                    or (tmp = '0169') then writeln('Thuoc mang Viettel')
            else writeln('Khong thuoc mang Viettel');
        end
    else writeln('Khong thuoc mang Viettel');
readln;
end.

bài 4

uses crt;

var

i，j，M，S: integer;

A，dem: array[1..100] of integer

begin

write(‘nhap do dai day so m:=’); readln(m);

for i:=1 to M do 

begin

write(‘A[‘，i，’]:=’); readln(A[i]);

end;

for i:=1 to M do

begin

for j:=1 to A[i] do

If (A[i] mod j = 0) then dem[i]=dem[i]+1;

end;

for i:=1 to M do

If (dem[i]>dem[i+1] then S:=A[i];

writeln(‘so tim duoc ‘，S);

readln

end;