Intel 8087 coprocessors
Intel introduced the 8086 processor in 1976. The math coprocessor that was paired with the chip - the 8087 - often was called the numeric data processor (NDP), the math coprocessor, or simply the math chip. The 8087 is designed to perform high-level math operations at many times the speed of the main processor. The primary advantage of using this chip is the increased execution speed in number crunching programs, such as spreadsheet applications.
Source: Upgrading and Repairing PCs (13th Edition) by Scott Mueller.