câu 1

program ct;

uses crt;

var i,n,s:integer;

begin

clrscr;

write('nhap n:=');readln(n);

s:=0;

for i:=1 to n do

if i mod 2=1 then s:=s+i;

writeln('tong la:',s);

readln

end.

câu 2:

program ct;

uses crt;

var i,s,n:integer;

begin

clrscr;

s:=0; n:=0;

while s<=300 do

  begin

      s:=s+n;

      n:=n+1;

  end;

    writeln('s:=',s);

readln

end.

câu 3:

program ct;

uses crt;

var i,s:integer;

begin

clrscr;

s:=8; i:=1

while s<=4 do

   begin

      s:=s-i;

      i:=i+1;

    end;

writeln('s:=',s);

readln

end.

1) program vandat;
uses crt;
var n,i,t : integer;
begin
t:=0;
 write('Nhap n:'); readln(n);
for i:=1 to n do if i mod 2=1 then t:=t+i;
write('Tong la :',t);readln end.

2) program vandat;
uses crt;
var n,i,t : integer;
begin
t:=0;
while t<=300 do begin i:=i+1; t:=t+i; end;
write('So N can tim :',i);
readln
end.

3) program vandat;
uses crt;
var s,i : integer;
begin
s:=8; i:=1;
while s<=4 do begin
s:=s-i; i:=i+1; end;
write('S=',s);
readln
end.