The numpad custom view is made of an EditText, or more accurately a FloatLabeledEditText. When the user clicks on the text field, the numpad appears instead of the standard keyboard.
The advantage of the numpad is that it appears near the text field and that you can further customize it as needed.
Note that it depends on ViewsEx v1.11+: https://www.b4x.com/android/forum/threads/updates-to-internal-libraries.59340/#post-406191 (make sure to copy it to the internal libraries folder).
As it is implemented as a custom view, you should add the Numpad class to your project with Numpad.bal layout file and then add one or more Numpads with the designer.
You can configure it from the designer:
It requires B4A v5.80+.
B4i implementation of this view: https://www.b4x.com/android/forum/threads/customview-numpad.64201/