a)
program ct;
uses crt;
var i,n:integer;
A:longint;
begin clrscr;
write('Nhap so n: '); readln(n);
A:=0;
for i:=1 to n do
A:=A+i;
writeln('Tong A la: ',A);
readln;
end.
b)
program ct;
uses crt;
var i,n:integer;
X:real;
begin clrscr;
write('Nhap so n: '); readln(n);
X:=0;
for i:=1 to n do
X:=X+(1/i);
writeln('Tong X la: ',X:4:2);
readln;
end.
Học tốt!