User`s manual

Math Coprocessor
If you process numeric data, a math coprocessor will make your work
more efficient .
An optional 80287 math coprocessor can be installed in socket U35 to
accelerate processing of calculation-intensive applications.
Remember that you must make sure the dotted end of the chip is lined
up with the notched end of the socket.
Refer to the illustration for
80287 math coprocessor below.
Math Coprocessor
(U35)
Figure 2-3: The Location of 80287
4 Chapter 2: Setting Up Your System