Bài 2:

program bt;
uses crt;
var i, n, s : integer;
a : array[1..100] of integer;
begin
        clrscr;
        write('Nhap so so nguyen: '); readln(n);
        for i:=1 to n do begin
         write('Nhap so thu ',i,': '); readln(a[i]);
        end;
        s := 0;
        write('Day so vua nhap la: ');
        for i:=1 to n do begin
         write(a[i],', ');
         s := s + a[i];
        end;
        writeln;
        writeln('Tong cac so trong day so la ',s);
        writeln('Trung binh cong cac so trong day so la ',s/n:0:2);
        readln
end.

Bài 3:

program bt;
uses crt;
var i, n, s, d : integer;
a : array[1..100] of integer;
begin
        clrscr;
        write('Nhap so so nguyen: '); readln(n);
        for i:=1 to n do begin
         write('Nhap so thu ',i,': '); readln(a[i]);
        end;
        s := 0; d := 0;
        for i:=1 to n do if (a[i] > 10) and (a[i] < 20) then begin
         d := d + 1;
         s := s + a[i];
        end;
        writeln('Co ',d,' so nho hon 10 va lon hon 20');
        write('Tong cac so lon hon 10 va be hon 20 la ',s);
        readln
end.

program bt;
uses crt;
var i, max : integer;
a : array[1..10] of integer;
begin
        clrscr;
        for i:=1 to 10 do begin
         write('Nhap so thu ',i,': '); readln(a[i]);
        end;
        max := 0;
        for i:=1 to 10 do if a[i] > max then max := a[i];
        if (max mod 2 = 0) then write(max,' la so lon nhat va la so chan')
        else write(max,' la so lon nhat va la so le');
        readln
end.

hảo

program bt;
uses crt;
var i, s, sa, sd, sc, sl, da, dd, dc, dl : integer;
a : array[1..50] of integer;
begin
        clrscr;
        for i:=1 to 10 do begin
         write('Nhap phan tu thu ',i,': '); readln(a[i]);
        end;
        write('Day so vua nhap la: ');
        for i:=1 to 10 do write(a[i],', ');
        writeln;
        s := 0; sa := 0; sd := 0; sc := 0; sl := 0; da := 0; dd := 0; dc := 0; dl := 0;
        for i:=1 to 10 do begin
         s := s + a[i];
         if (a[i] > 0) then begin sd := sd + a[i]; dd := dd + 1 end;
         if (a[i] < 0) then begin sa := sa + a[i]; da := da + 1 end;
         if (a[i] mod 2 = 0) then begin sc := sc + a[i]; dc := dc + 1; end
         else begin sl := sl + a[i]; dl := dl + 1 end;
        end;
        writeln('Tong cac phan tu trong mang la ',s);
        writeln('Trung binh cong cac phan tu trong mang la ',s/10);
        writeln('Tong cac so am la ',sa);
        writeln('Tong cac so duong la ',sd);
        writeln('Tong cac so chan la ',sc);
        writeln('Tong cac so le la ',sl);
        writeln('So cac so am la ', da);
        writeln('So cac so duong la ', dd);
        writeln('So cac so chan la ', dc);
        writeln('So cac so le la ', dl);
        readln
end.