lib64gmpxx4 software package provides Multiprecision arithmetic library (C++ bindings, 64bit), you can install in your Debian 7 (Wheezy) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install lib64gmpxx4
lib64gmpxx4 is installed in your system.
Make ensure the lib64gmpxx4 package were installed using the commands given below,
$ sudo dpkg-query -l | grep lib64gmpxx4 *
You will get with lib64gmpxx4 package name, version, architecture and description in a table
| Distro | Debian 7 wheezy |
| Section | Libraries |
| Package | lib64gmpxx4 |
| Version | 2:5.0.5+dfsg-2 |
| Description | Multiprecision arithmetic library (C++ bindings, 64bit) |
| Sub Section | libs |