Viết chương trình nhập vào số nguyên n và tính tổng các số lẻ (các số lẻ là số không chia hết cho 2) trong khoảng từ 1 đến n ( ví dụ nhập = 10, ta sẽ có tổng sau s=1+3+5+7+9=25)

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(s);

readln;

end.

Câu 1: 

uses crt;

var a:array[1..100]of integer;

i,n,t,s:integer;

begin

clrscr;

write('Nhap n='); readln(n);

for i:=1 to n do 

  begin

write('A[',i,']='); readln(a[i]);

end;

t:=0;

s:=1;

dem:=0;

for i:=1 to n do 

  if a[i] mod 3=0 then 

begin

inc(dem);

t:=t+a[i];

s:=s*a[i];

end;

if dem=0 then writeln('Khong co so chia het cho 3 trong day')

else begin

writeln('Tong cac so chia het cho 3 la: ',t);

writeln('Tich cac so chia het cho 3 la: ',s);

end;

readln;

end.

Câu 2: 

uses crt;

var a:array[1..100]of integer;

i,n,dem,t:integer;

begin

clrscr;

write('Nhap n='); readln(n);

for i:=1 to n do 

  begin

write('A[',i,']='); readln(a[i]);

end;

dem:=0;

t:=0;

for i:=1 to n do 

 if a[i] mod 2=0 then 

begin

inc(dem);

t:=t+a[i];

end;

writeln('So so chan la: ',dem);

writeln('Tong cac so chan la: ',t);

readln;

end.

Câu 3: 

uses crt;

var a:array[1..100]of integer;

i,n,dem1,dem2,t1,t2,s1,s2:integer;

begin

clrscr;

write('Nhap n='); readln(n);

for i:=1 to n do 

  begin

write('A[',i,']='); readln(a[i]);

end;

dem1:=0;

dem2:=0;

t1:=0;

t2:=0;

s1:=1;

s2:=1;

for i:=1 to n do

begin

if a[i] mod 2=0 then 

begin

inc(dem1);

t1:=t1+a[i];

s1:=s1*a[i];

end

else begin

inc(dem2);

t2:=t2+a[i];

s2:=s2*a[i];

end;

end;

if dem1=0 then writeln('Khong co so chan trong day')

else begin

writeln('So so chan la: ',dem1);

writeln('Tong cac so chan la: ',t1);

writeln('Tich cac so chan la: ',s1);

end;

if dem2=0 then writeln('Khong co so le trong day')

else begin

writeln('So so le la: ',dem2);

writeln('Tong cac so le la: ',t2);

writeln('Tich cac so le la: ',s2);

end;

readln;

end.

uses crt;

var a:array[1..100]of integer;

i,n,t:integer;

begin

clrscr;

write('Nhap n='); readln(n);

for i:=1 to n do 

  begin

write('A[',i,']='); readln(a[i]);

end;

t:=0;

for i:=1 to n do 

  if (a[i] mod 2=0) and (a[i] mod 3=0) then t:=t+a[i];

writeln(t);

readln;

end.

uses crt;

var i,n,d:longint;

begin 

d:=0;

writeln('nhapn=');read(n);

for i:=1 to n do

begin

if i mod 3=0 then write(i,' ');

if i mod 3=0 then d:=d+i;

end;

writeln('tong=',d);

readln;

end;

Program HOC24;

var i,n: integer;

a: array[1..10000] of integer;

t: longint;

begin

write('Nhap N: '); readln(n);

for i:=1 to n do 

begin

write('A[',i,']='); readln(a[i]);

end;

t:=0;

for i:=1 to n do if (a[i] mod 3=0) and (a[i] mod 5=0) then t:=t+a[i];

write('Tong la: ',t);

readln

end.

Program HOC24;

var i: byte;

t: integer;

begin

t:=0;

for i:=2 to 98 do if i mod 5=0 then t:=t+i;

write('Tong cac so chia het cho 5 tu 2 den 98 la: ',t);

readln

end.

Program tinhtong;
uses crt;
var i, SUM, N : integer;
Begin
Clrscr;
Write('Nhap N: '); Readln(n);
SUM := 0; For i:=1 to N do if (i mod 3 = 0) then SUM:= SUM + i;
Write('Tong la: ', SUM);
Readln;
End.

(3+6+9+12+18+21+27+33+36+42+45+48+52+54+60+63+66++69+72+75+78+81+84+87+90+93+96+99)⋮3

#include <bits/stdc++.h>

using namespace std;

int t,i;

int main()

{

t=0;

for (i=1; i<=100; i++)

if (i%3==0) t=t+i;

cout<<t;

return 0;

}

uses crt;

var i,t:integer;

begin

clrscr;

t:=0;

for i:=1 to 12 do 

  if i mod 2=0 then t:=t+i;

writeln(t);

readln;

end.