Math Coprocessor
The Math Coprocessor is a second processor in your computer that does nothing but number crunching for the system. Addition, subtraction, multiplication, and division of simple numbers is not the coprocessors job. It does all the calculations involving floating point (decimal) numbers, such as scientific calculations and algebraic functions.

These functions and calculations are used in much of the computer's routines and just about every software available. Spreadsheets contain statistical calculations, word processors deal with line spacing, font size and justification, and of course, any graphics or animation software is relying heavily on number crunching. The Central Processing Unit (CPU) is perfectly capable of doing these functions and calculations. As a matter of fact, that used to be part of its job. Most of the older computers (pre-486) were sold without coprocessors. So the CPU had to process all the computer's hardware and software functions, handle all interrupt requests (we'll talk later), and direct all information and data, as well as performing all floating point calculations. This required a lot of the processor's time.

By having a second processor, or 'coprocessor', to take over the number crunching, it can free up a lot of the CPU's precious time. This would allow the Central Processing Unit to focus all of its resources on the other functions it has to perform, thus increasing the overall speed and performance of the entire system. It's not like this was a great revelation that came over the scientific community in the midst of home computer development. The absence of a math coprocessor in early home computer systems was a matter of keeping production costs down. The advantage was recognized right from the beginning, and most of these motherboards had an empty slot for the aftermarket addition of a coprocessor. The number (or name) of the math coprocessor followed the CPU's numbering sequence, only the last digit would be a '7', not a '6'. If you had an 8086 CPU then you could add an 8087 coprocessor. For an 80286 you would install an 80287, etc..