3/

uses crt;

var a: array[1..100] of integer;

i,n,s: integer;

begin

clrscr;

write ('nhap so phan tu: ');  readln (n);

for i:=1 to n do

begin

write ('nhap phan tu thu ',i,': ');  readln (a[i]);

s:=s+a[i];

end;

writeln ('trung binh cong: ',s/n:1:2);

readln;

end.

4/

uses crt;

var n,d: integer;

begin

clrscr;

write ('nhap n: ');  readln (n);

d:=0;

while n<>0 do

begin

n:=n div 10;

d:=d+1;

end;

writeln ('N co ',d,' chu so');

readln;

end.

Câu 3 :

uses crt;

var K : array [1 .. 100] of real;

    i, N : integer; T : real;

begin

clrscr;

write('Nhap so N = '); readln(N);

i := 1; T := 0;

while i <= N do

    begin

        write('Nhap so thu ', i ,' = '); readln(K[i]);

        T := T + K[i];

        i := i + 1;

    end;

write('Trung binh cong cac phan tu = ', T / N : 2 : 1);

readln

end.

Câu 4 :

uses crt;

var N, i , K, d : longint;

begin

clrscr;

write('Nhap so N = '); readln(N);

d := 0;

while N  > 0 do

    begin

        i := N div 10;

        k := N - (i * 10);

        N := N div 10;

        d := d + 1;

    end;

write('N co ', d ,' chu so');

readln

end.