1, Cloud solution. Fire up a million instances of Windows7 on Azure and upgrade to Windows10. Restore them and repeat 1000 times
2, RIAA solution. Download a pirate copy. Claim that this represents a million potential violations who would have purchased a copy. And they had a 48x CD drive so that counts 48x as much. Repeat 20 times
3, Oracle solution. Install on a machine with an 8 core CPU. Claim that this represents 2^8 licenses in use.
4, Google/Apple solution. Claim that you have a billion installs but they all happened in Ireland and so you don't count them when reporting to the IRS.