Im trying to understand how virtual machines work with relation to host.

Lets say my host has an 8 core cpu and 16gb ram

I want to create some virtual machines. Does this mean I can create 3x (2 core + 4gb) virtual machines leaving 2 cores and 4gb of ram for the host?

Like does it equate 1=1 or is virtualization different?

If i did 4x (2core + 4gb ram) machines, would this technically be all the resources of the host and unable to run if all were running at the same time?

Thanks for helping my noob brain understand how virtualization works with regards to host and resources