Functionality wise youi have done a very good job so far.
Make sure to improve on design and usability. For example:
For background color is better choose something light-colored so the text has sufficient contrast
Make sure your text is approrpiately sized
For numbers, if you are providing your own, custom keyboard, make sure the buttons are big enough and they are layed down in rows of 3 llike the numeric pad of a normal keyboard. Note however, that if you use a form with input set to "integer" the mobile device's keyboard will show up already at the right mode (i.e. ready to accept numeric digits only).
Functionality wise youi have done a very good job so far. Make sure to improve on design and usability. For example: For background color is better choose something light-colored so the text has sufficient contrast Make sure your text is approrpiately sized For numbers, if you are providing your own, custom keyboard, make sure the buttons are big enough and they are layed down in rows of 3 llike the numeric pad of a normal keyboard. Note however, that if you use a form with input set to "integer" the mobile device's keyboard will show up already at the right mode (i.e. ready to accept numeric digits only).