Round-Off Error

The difference between the exact mathematical solution and a solution reached through rounding approximation during the calculations (known also as rounding error). The main reason to be concerned about round-off errors is that despite their seemingly small size when considered in the context of one calculation, their effects may potentially accumulate and not cancel each other out. As a result, in some circumstances, the exact solution and a solution reached in calculations that involved round-off errors can be substantially different.