php5-gmp software package provides GMP module for php5, you can install in your Ubuntu 14.04 LTS (Trusty Tahr) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install php5-gmp
php5-gmp is installed in your system.
Make ensure the php5-gmp package were installed using the commands given below,
$ sudo dpkg-query -l | grep php5-gmp *
You will get with php5-gmp package name, version, architecture and description in a table
| Distro | Ubuntu 14 04 lts trusty tahr |
| Section | PHP |
| Package | php5-gmp |
| Version | 5.5.9+dfsg-1ubuntu4.20 [amd64, |
| Description | GMP module for php5 |
| Sub Section | PHP |