Bài 8: 

program bt8;
uses crt;
var m,n,i,dem:integer;
begin
 clrscr;
 write('Nhap m,n: '); readln(m,n);
 For i:=m to n do if i mod 2=0 then inc(dem);
 writeln('Co ',dem,' so chan trong day');
 readln;
end.

Bài 9:

program bt9;
uses crt;
var m,n,i,dem:integer;
begin
 clrscr;
 write('Nhap m,n: '); readln(m,n);
 For i:=m to n do if i mod 2<>0 then inc(dem);
 writeln('Co ',dem,' so le trong day');
 readln;
end.

Bài 10: 

program bt10;
uses crt;
var n,i,S:integer;
    A:array[1..250] of integer;
begin
 clrscr;
 readln(n);
 For i:=1 to n do
  begin
   read(A[i]);
   if A[i] mod 2 =0 then S:=S+A[i];
  end;
 writeln(S);
 readln;
end.

8.
var m,n,i,d:longint;
begin
write('Nhap m,n: '); readln(m,n);
for i:=m to n do

if i mod 2=0 then inc(d);
writeln('So so chan: ',d);
readln
end.

9.

var m,i,n,d: integer;
begin
write('Nhap m,n: '); readln(m,n);
for i:=m to n do

if i mod 2 <> 0 then inc(d);
writeln('So so le: ',d);
readln
end.

10.

var n,i,s: longint;
    a:array[1..250] of longint;
begin
write('Nhap n: ');readln(n);
For i:=1 to n do

begin
read(s[i]);
if a[i] mod 2 =0 then s:=s+a[i];

end;
writeln('S = ',s);
readln;
end.