A floating point unit (FPU) is a part of a computer system specially designed to carry out operations on floating point numbers. Typical operations are addition, subtraction, multiplication, division, and square root.
Some systems can also perform more advanced functions as exponential or trigonometric functions calculations, however in most modern processors these functions are done with software library routines, not by hardware.
In most modern general purpose CPUs, one or more FPUs are integrated inside the CPU; however many embedded microcontrollers, especially older designs, do not have hardware support for floating point operations.
Most modern computers have integrated FPU hardware; but not all. In the absence of an FPU, many FPU functions can be emulated, which saves the added hardware cost of an FPU but is significantly slower.