Câu 1:
var i, n, a: longint;
sum: longint;
BEGIN
readln(n);
sum:=0;
for i:=1 to n do
begin
readln(a);
if (a mod 2 = 0) and (i mod 2 = 1) then sum:=sum+a;
end;
writeln('Tong cac phan tu la so chan o vi tri le la: ',sum);
readln;
END.
Câu 2:
var i, n, a: longint;
dem: longint;
BEGIN
readln(n);
dem:=0;
for i:=1 to n do
begin
readln(a);
if (a mod 2 = 0) then inc(dem);
end;
writeln('So luong cac phan tu la so chan la: ',dem);
readln;
END.