There is no Mac 10 that I know about. Rather, the MacBook Pro, IMac, and Mac Mini all run Mac’s Operating System (OS) Mojave (if current). In addition to my iMac, I also own a Mac Mini and an iMac 21.5” with the current version 10 (actually 10.14.3, I think). Memory (which is referred to as Memory when you click on the Apple in the upper left-hand corner of the screen (eve of a display unit) and choose “About This Mac.” Each one of mine is an i7 chip with only 8 GB of Memory, which is operating memory where the program actually runs (or programs are running). When you save data files or other files, they are stored on an HD or hard disk, which will run from 500 GB to double that or more; however, solid state drives are faster and less complicated, so you might choose 500 GB of Solid State Hard Drive over 1 terrabite or 1,000 GB of storage. I chose a less expensive 500 GB because I also store a lot of stuff “in the cloud,” which (in my case) means I upload to Apple’s iCloud Drive so that I can work on files on any of my 3 computers easily. ASK THE SALES STAFF AT BEST BUY TO SHOW YOU WHAT I AM SAYING! You can also sign up to take a tutorial class at a local Apple Store if one is near you.