$ sudo apt-get update
$ sudo apt-get install ibus-input-pad 

ibus-input-pad is installed in your system.

Make ensure the ibus-input-pad package were installed using the commands given below,

$ sudo dpkg-query -l | grep ibus-input-pad *

You will get with ibus-input-pad package name, version, architecture and description in a table

ibus-input-pad package basic information: