$ sudo apt-get update
$ sudo apt-get install libfsharp-core4.3-cil 

libfsharp-core4.3-cil is installed in your system.

Make ensure the libfsharp-core4.3-cil package were installed using the commands given below,

$ sudo dpkg-query -l | grep libfsharp-core4.3-cil *

You will get with libfsharp-core4.3-cil package name, version, architecture and description in a table

libfsharp-core4.3-cil package basic information: