1.
uses crt;
var n,i,s:longint;
begin
clrscr;
write('n= ');readln(n);
for i:=1 to n do
s:=s+i;
writeln('S= ',s);
readln
end.
2.
uses crt;
var n,m,i,d:longint;
begin
clrscr;
write('m,n= (m<n) ');readln(m,n);
for i:=m to n do
if i mod 2=0 then inc(d);
writeln('Co ',d,' so chia het cho 2 trong pham vi tu m den n');
readln
end.