The ALU runs all of the arithmatec and logic it does math
CU (Control Unit)
The control unit (CU) is a component of a computer's central processing unit (CPU) that directs operation of the processor. It tells the computer's memory, arithmetic/logic unit and input and output devices how to respond to a program's instructions
In computer architecture, a processor register is a small amount of storage available as part of a digital processor, such as a central processing unit (CPU). Such registers are typically addressed by mechanisms other than main memory and can be accessed faster.