Bài 1:
program Tin_hoc;
uses crt;
var i,n:integer;
s:real;
begin
clrscr;
write('Nhap n: ');readln(n);
s:=0;
for i:= 1 to n do s:= s + 1/i;
writeln('S = ',s);
readln;
end.
Bài 2:
program Tin_hoc;
uses crt;
var n,i,tong:integer;
begin
clrscr;
write('Nhap n: ');readln(n);
tong:=0;
for i:= 1 to n do if i mod 3 = 0 then tong:=tong+i;
writeln('Tong cac so nguyen <=',n,' va chia het cho 3 la: ',tong);
readln;
end.
Bài 3:
program t;
uses crt;
var i,tong:integer;
begin
clrscr;
tong:=0;
for i:= 1 to 100 do tong:=tong+i;
writeln ('Tong cua 100 so tu nhien dau tien la: ',tong);
readln;
end.