Đâu bạn... 

Câu 1: B,C

Câu 2: B

(3+2) div 6 -4 = 5 div 6 -4 = 0-4=-4

uses crt;
var e,f,i,a,b,c,d: byte;
begin
clrscr;
write('Tu so = '); readln(e);
write('Mau so = '); readln(f);

a:=e;
b:=f;

writeln('Phan so ban dau: ',e,'/',f);

while E <> F do
if E > F then E:=E-F
else F:=F-E;

If e <> 1 then
begin
a:=a div e;
b:=b div e;
write('Phan so toi gian: ',a,'/',b);
end
else write('Phan so da toi gian, ',a,'/',b);
readln
end.

dùng for do thay while do dùm mình với

1.

Program HOC24;

var a: array[1..32000] of longint;

i,n: integer;

tc,tl: longint;

begin

write('Nhap N: '); readln(n);

tc:=0; tl:=0;

for i:=1 to n do 

begin

write('a[',i,']='); readln(a[i]);

if a[i] mod 2=0 then tc:=tc+a[i];

if a[i] mod 2=1 then tl:=tl+a[i];

end;

writeln('Tong chan la: ',tc);

write('Tong le la: ',tl);

readln

end.

2.

Program HOC24;

var a: array[1..32000] of longint;

d1,d2,i,n: integer;

begin

write('Nhap N: '); readln(n);

d1:=0; d2:=0;

for i:=1 to n do 

begin

write('a[',i,']='); readln(a[i]);

if a[i] >0 then d1:=d1+1;

if a[i] <0 then d2:=d2+1;

end;

writeln('Co ',d1,' so lon hon 0');

write('Co ',d2,' so be hon 0');

readln

end.

uses crt;

var n,i,s:integer;

begin

clrscr;

n:=1;

s:=0;

repeat

s:=s+n;

n:=n+1;

until s>1000;

writeln(n);

readln;

end.

program XuatSoChan;
uses crt;
const
  Max_N = 20;
type
  MangSoNguyen = array [1..Max_N] of integer;
var
  A: MangSoNguyen;
  i, n: integer;
begin
  clrscr;
  write('Nhap so luong phan tu cua mang: ');
  readln(n);
  writeln('Nhap cac phan tu vao mang:');
  for i := 1 to n do
  begin
    write('A[', i, ']: ');
    readln(A[i]);
  end;
  writeln('Cac so chan trong mang la:');
  for i := 1 to n do
  begin
    if A[i] mod 2 = 0 then
      writeln(A[i]);
  end;
  readln;
end.

uses crt;

var i,n,t:integer;

begin

clrscr;

readln(n);

t:=0;

for i:=1 to n do t:=t+i;

writeln(t);

readln;

end.