I have installed office 2016 RTM x64 when it first appeared, to my surprise, the Mathematics add in that allows you to utilize Microsoft Mathematics 4.0 gave an error that it cannot work on other than Office 2013... I searched the forums and it seems every one is saying the same... Today, I installed Office 2016 x64 VL on Windows 10 B10558 then Mathematics 4.0 x64 and then the Mathematics Add In, and I was pleasantly surprised that it works. I wanted to share this with those who were waiting for a solutions.