- Does the calculations
- Everything else in the computer is there to service this unit
- Handles integers
- May handle floating point (real) numbers
- May be separate FPU (maths co-processor)
- May be on chip separate FPU (486DX +)
ALU Inputs and Outputs
Integer Representation
- Only have 0 & 1 to represent everything
- Positive numbers stored in binary
— e.g. 41=00101001
- No minus sign
- No period
- Sign-Magnitude
- Two’s compliment
