Bài 1.

Program BT 1;

uses crt;
var i,n: integer;

s:real;
begin
clrscr;
write('Nhap so n: '); readln(n);
if n>50  then
begin
for i:=1 to n do if i mod 3 = 0 then s:=s+i;
write('Tong số S =',s);
end
else write('N<50, vui long nhap lai');
readln;
end.

Bài 2.

program BT2;

Uses crt;
var k,i: integer;
begin
clrscr;
write('Nhap k: '); readln(k);
if k>20 then
begin
write('Cac so chia het cho 5 la: ');
for i:=0 to k do if i mod 5 = 0 then write(i,' ');
end
else write('k<=20, sai hay nhap lai!');
readln;
end.

Cho mk xin 5 sao + hay nhất

1.

uses crt;
var i,n,s: integer;
begin
clrscr;
write('Nhap n: '); readln(n);
s:=0;
if n>50 then
begin
for i:=1 to n do if i mod 3 = 0 then s:=s+i;
write('Tong=',s);
end
else write('N<50, vui long nhap lai');
readln
end.

2.

uses crt;
var k,i: integer;
begin
clrscr;
write('Nhap k: '); readln(k);
if k>20 then
begin
write('Cac so chia het cho 5 la: ');
for i:=0 to k do if i mod 5 = 0 then write(i,' ');
end
else write('k<=20, vui long nhap lai!');
readln
end.