câu 1 :

uses crt;
var a:array[1..100]of integer;
i,n,t,max:integer;
tbc:real;
begin
clrscr;
write('nhap so phan tu:'); readln(n);
for i:=1 to n do
begin
write('a[',i,']='); readln(a[i]);
end;
{--------------xuat----------------------------}
for i:=1 to n do write(a[i]:2);
{--------------tinh-trung-binh-cong--------------------}
writeln;
t:=0;
for i:=1 to n do
begin
t:=t+a[i];
end;
tbc:=t/n;
write(tbc:4:2);
{----------------------phan-tu-co-gia-tri-max-va-khoang-cach----------------}
max:=a[1];
for i:=1 to n do
if max<a[i] then max:=a[i];
writeln('phan tu lon nhat la: ',max);
readln;
end.

xin lỗi bạn , mình mới chỉ làm được nhiêu đó

câu 2:

uses crt;
var a:array[1..100]of integer;
n,dem,dem1,dem2,dem3,i:integer;
t,dem4,max,j:integer;
begin
clrscr;
{------------------cau-a-------------------------}
writeln('cau a:');
write('n='); readln(n);
for i:=1 to n do
begin
write('a[',i,']='); readln(a[i]);
end;
for i:=1 to n do
write(a[i]:4);
{--------------cau-b-----------------------------}
writeln;
writeln('cau b:');
writeln('{--------------------------------}');
dem:=0;
dem1:=0;
dem2:=0;
dem3:=0;
for i:=1 to n do
begin
if a[i]>0 then dem:=dem+1;
if a[i]<0 then dem1:=dem1+1;
if a[i] mod 2=0 then inc(dem2);
if a[i] mod 2=1 then inc(dem3);
end;
writeln('so luong so duong la: ',dem);
writeln('cac so duong la: ');
for i:=1 to n do
if a[i]>0 then write(a[i]:4);
writeln;
writeln('{--------------------------------}');
writeln('so luong so am la: ',dem1);
writeln('cac so am la: ');
for i:=1 to n do
if a[i]<0 then write(a[i]:4);
writeln;
writeln('{--------------------------------}');
writeln('so luong so chan la: ',dem2);
writeln('cac so chan la: ');
for i:=1 to n do
if a[i] mod 2=0 then write(a[i]:4);
writeln;
writeln('{--------------------------------}');
writeln('so luong so le la: ',dem3);
writeln('cac so le la: ');
for i:=1 to n do
if a[i] mod 2=1 then write(a[i]:4);
writeln;
writeln('{--------------------------------}');
{------------------cau-c--------------------------}
writeln('cau c:');
t:=0;
dem4:=0;
for i:=1 to n do
if (a[i]>2) and (a[i]<5) then
begin
inc(dem4);
t:=t+a[i];
end;
writeln('so phan tu vua lon hon 2 vua be hon 5 trong day so la: ',dem4);
writeln('tong cua cac phan tu vua lon hon 2 vua be hon 5 trong day so la: ',t);
{---------------cau-d-----------------------------}
writeln('cau d:');
max:=a[1];
for i:=1 to n do
if max<a[i] then max:=a[i];
writeln('phan tu lon nhat trong day so la: ',max);
writeln('cac uoc cua ',max,' la: ');
for j:=1 to max do
if max mod j=0 then write(j:4);
readln;
end.

program BTH;
uses Crt;
var s:Real;
n,i,k:LongInt;
begin
clrscr;
Write('Nhap n: ');readln(n);
For i:=1 to n do
Begin
Write('Nhap so thu ',i,' : ');readln(k);
s:=s+k;
end;
writeln('TBC day so tren la: ',s/i:4:2);
end.