a)

program tinh_tong;

uses crt;

var n,i:integer;

tong:longint;

begin

clrscr;

write('nhap so n:');readln(n);

i:=1;tong:=0

while i<n do

begin

if i mod 2=1 then tong:=tong+i

else i:=i+1;

end;

tong:=tong+2*n;

writeln('tong la:',tong);

readln;

end.

b)

program tinh_tong;

uses crt;

var n,i:integer;

tong:longint;

begin

clrscr;

write('nhap so n:');readln(n);

i:=1;tong:=0

while i<n do

begin

if i mod 2=0 then tong:=tong+i

else i:=i+1;

end;

tong:=tong+(2*n-1);

writeln('tong la:',tong);

readln;

end.

b) uses crt;

var i,n,t:integer;

begin

clrscr;

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

t:=0;

i:=1;

while i<=2*n-1 do 

  begin

  i:=i+1;

if i mod 2=0 then t:=t+i;

end;

writeln(t);

readln;

end.

Câu 1: 

uses crt;

var n,i,t:integer;

begin

clrscr;

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

t:=0;

for i:=1 to n do 

 t:=t+i;

writeln(t);

readln;

end.

program tinh_quang_duong;

uses crt;

var t:integer;

function qd:longint;

begin

qd:=40*t;

end;

begin

clrscr;

write('nhap thoi gian:');readln(t);

write('quang duong oto di duoc sau ',t,' gio la: ',qd);

readln;

end.

program tim_tong_va_tich;

uses crt;

var n,i:integer;

tong,tich:longint;

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

begin

write('nhap so n:');readln(n);

i:=1;tich:=1;tong:=0;

while i<=n do

begin

write('nhap phan tu a[',i,']:');readln(a[i]);

tong:=tong+a[i];tich:=tich+a[i];

i:=i+1;

end;

writeln('tong cua cac so tren la:',tong);

writeln('tich cua cac so tren la:',tich);

readln;

end.

Program Hinh_Tamgiac_Program;
Uses crt;
Var a,b,c,s,p : real;
Begin
Clrscr;
Writeln(‘HINH TAM GIAC:’);
Write(‘nhap a =’);readln(a);
Write (‘nhap b =’);readln(b); Write(‘nhap c =’);readln(c);
If ((a+b)>c)and((b+c)>a)and((a+c)>b) then
Begin
p:=(a+b+c)/2;
s:=sqrt(p*(p-a)*(p-b)*(p-c)); Writeln(‘Chu vi tam giac:’,2*p:4:2) ; Writeln(‘Dien tich tam giac:’,s:4:2);
End
Else
Writeln(a,’, ‘, b,’, ‘, c, ‘ khong phai la ba canh cua tam giac’) ;
Readln;
End.

program dem_so;

uses crt;

var i,n,dem,k:longint;

a:array[1..100]of longint;

begin

clrscr;

write('nhap so n:');readln(n);

for i:=1 to n do

begin

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

end;

dem:=0;

write('nhap so k:');readln(k);

for i:=1 to n do

if a[i]=k then dem:=dem+1;

if dem=0 then write(k,' khong co trong day so tren');

readln;

end.

program tinh_tong;

uses crt;

var i,n:integer;

s:real;

begin

clrscr;

write('nhap n:');readln(n);

for i:=1 to n*2-1 do

if i mod 2=1 then s:=s+1/i;

writeln('tong la: ',s);

readln;

end.

program tinh_tong;

uses crt;

var i,n:integer;

s:real;

begin

clrscr;

write('nhap n:');readln(n);

i:=1;

while i<=n*2-1 do

begin

s:=s+1/i;

i:=i+2;

end;

writeln('tong la: ',s);

readln;

end.

a) S=20

program hotrotinhoc;

var n,i.d: integer;

t: longint;

begin

readln(n);

t:=0; d:=0;

for i:=1 to n do

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

writeln('Tong cac so chia het cho 3 tu 1 den n la:',t);

for i:=1 to n do

if i mod 3=0 then inc(d);

write('Co ',d,' so chia het cho 3 tu 1 den N');

readln

end.

Bạn tham khảo nhé!

uses crt;

var a,b,t,i:integer;

begin

clrscr;

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

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

t:=0;

for i:=a to b do 

  if i mod 3=0 then t:=t+i;

writeln(t);

readln;

end.