CÂU A:

program bai_giai;
uses crt;
var n,i,d:longint;a:array[1..1000]of longint;
begin
 clrscr;
  write('nhap n:=');readln(n);
  d:=0;
  for i:=1 to n do
        begin
         write('a[',i,']=');readln(a[i]);
         if(a[i]=5)then inc(d);
        end;
  write('co ',d,' so hang bang 5');
 readln;
end.

CÂU B:

program bai_giai;
uses crt;
var n,i,s:longint;a:array[1..1000]of longint;
begin
 clrscr;
  write('nhap n:=');readln(n);
  s:=0;
  for i:=1 to n do
        begin
         write('a[',i,']=');readln(a[i]);
         if(a[i]>0)then s:=s+a[i];
        end;
  write('tong cac so duong trong day la:',s);
 readln;
end.

CÂU C:

program bai_giai;
uses crt;
var n,i,s:longint;a:array[1..1000]of longint;
begin
 clrscr;
  write('nhap n:=');readln(n);
  s:=0;
  for i:=1 to n do
        begin
         write('a[',i,']=');readln(a[i]);
         if(a[i]<0)then s:=s+a[i];
        end;
  write('tong cac so am trong day la:',s);
 readln;
end.

program sksk;
uses crt;
var a : array[1..100]of integer;
    i, s1, s2, dem, n   : integer;
begin
clrscr;
write(' nhap so phan tu co trong day : '); readln( n);
s1:= 0;
s2:= 0;
dem:= 0;
for i:= 1 to n do 
begin
write(' nhap phan tu thu', i ,':'); readln( a[i]);
if a[i] = 5 then dem := dem+ 1;
if a[i] > 0 then s1 := s1 + a[i];
if a[i] < 0 then s2 := s2 + a[i];
end;
writeln(' so phan tu co gia tri bang 5 la :', dem );
writeln(' tog cac so duong trong day la :', s1 );
writeln(' tong cac so am trong day la :', s2 );
readln
end.