To review the number of CPU Cores on your machine, there are 2 methods:

System Report

1. Navigate towards the top left corner of your screen and click the Apple Logo
2. Click "About this mac" > "System Report" > "Hardware"
3. The number of CPU Cores should be listed in the Hardware overview, to the right of "Total number of Cores"

Terminal

1. Launch the "Terminal" Application
2. Type and enter the command:  sysctl -n hw.ncpu
3. The resulting output will provide the number of cores