Hi guy’s this post , i’m going to explain , how to add textbox , multiply textbox in ASP.NET
First add four textbox and four label controls and enable AutoPostBack Property True.

Create one method ( Txt() ) and click on textbox, you can see TextChanged Event of TextBox open. Write the below codes.

- After Writing All Above Codes. Enter checkbox some numeric values and you’ll get suitable result.

Happy Coding , Thanks.