C1:

uses crt;
var a:array[1..500]of integer;
    n,i:integer;
Begin
    clrscr;
    write('n = ');readln(n);
    for i:=1 to n do
    begin 
        write('a[',i,'] = ');readln(a[i]);
    end;
    write('day sau khi nhap: ');
    for i:=1 to n do write(a[i],' ');
    readln
End.

C2:

uses crt;
var a:array[1..500]of integer;
    n,i,t:integer;
Begin
    clrscr;
    write('n = ');readln(n);
    for i:=1 to n do
    begin 
        write('a[',i,'] = ');readln(a[i]);
        t:=t+a[i];
    end;
    write('tong = ',t);
    readln
End.

C3:

uses crt;
var a:array[1..500]of integer;
    n,i,max,min:integer;
Begin
    clrscr;
    write('n = ');readln(n);
    for i:=1 to n do
    begin 
        write('a[',i,'] = ');readln(a[i]);
    end;
    max:=a[1]; min:=a[1];
    for i:=1 to n do
    begin  
        if a[i]>max then max:=a[i];
        if a[i]<min then min:=a[i];
    end;
    writeln('so lon nhat: ',max);
    write('so nho nhat: ',min);
    readln
End.

C4:

uses crt;
var a:array[1..500]of integer;
    t,v:array[1..100]of real;
    n,i:integer;
Begin
    clrscr;
    write('so h/s: ');readln(n);
    for i:=1 to n do
    begin 
        writeln('h/s[',i,']:');
        write('diem toan: ');readln(t[i]);
        write('diem van: ');readln(v[i]);
    end;
    for i:=1 to n do
        writeln('diem trung binh cua h/s[',i,']: ',(t[i]+v[i])/2:2:1);
    readln
End.