2.

program b2;
uses crt;
var a,b:integer;
    c:real;
Begin
        clrscr;
        write('a = ');readln(a);
        write('b = ');readln(b);
        c:=a/b;
        write('Thuong 2 so = ',c:2:2);
        readln
End.

4.

program b4;
uses crt;
var a,b,c,max:integer;
Begin
        clrscr;
        write('a = ');readln(a);
        write('b = ');readln(b);
        write('c = ');readln(c);
        max:=a;
        if max<b then max:=b;
        if max<c then max:=c;
        write('Gia tri lon nhat: ',max);
        readln
End.

Câu 2: 

Program baitap;

Uses crt;

Var a,b:integer;

      c:real;

Begin

Write('Nhap lan luot hai so a va b:');

Readln(a,b);

If a>=b then c:=a/b;

If b>a then c:=b/a;

Writeln('Thuong cua hai so do:',c);

Readln

End.

Câu 4:

Program baitap;

Uses crt;

Var max,b,c:integer;

Begin

Clrscr;

Write('Nhap a:'); Readln(max);

Write('Nhap b:'); Readln(b);

Write('Nhap c:'); Readln(c);

If b>max then max:=b;

If c>max then max:=c;

Writeln('So lon nhat:',max);

Readln

End.