display Fractions with input fields in ASP.NET

Question

Hi all

 I have a scenario in which I need to design online keyboard with buttons implementing different mathematical functions in ASP.NET. For example 

1) A button called "Fraction" Onclicking=> should display A numerator and a denominator separated by '-' with empty fields.  Just as we write fractions manually. Now when the user clicks on this button the cursor should focus on numerator displaying 'the division line' and then by pressing 'Down' arrow key(on computr keyboard) should focus on denominator allowing users to enter both fields. Keeping it simple the user should be able to toggle between numerator and denominator.

Please help me with a sample. I have got no idea.

Thanks in advance