Definition of rounding

1. Banking. In consumer credit, the allowed tolerance in computing the Annual Percentage Rate (APR) finance charge disclosed in loan agreements. Federal Reserve Regulation Z allows rate varia tions as much as 1/8 of 1% above, or below, the exact interest rate. For example, an annual percentage rate of 10.3333 may be stated as 10.33%, 10.3%, or 10.25%.
2. Finance. The practice of shortening publicly disclosed information by adjusting a figure upward or downward to the nearest whole number. The practice simplifies disclosure in annual reports, for example, when zeroes are omitted, and conveys to the casual observer the same information as the fully expressed data.

the act of replacing a number with the nearest number that has a smaller number of significant digits. For example, 2.76 rounded to one decimal place is 2.8. The rule is that if the first digit to be discarded is 5 or greater, the last digit that is kept should be increased. Thus 2.74 → 2.7, but 2.76 → 2.8. Contrast truncation.

There is a big difference between rounding a number, which actually changes it, and simply printing it with a limited number of decimal places (see printf). In the latter case, the number itself is not changed, and its original value remains available for further computation.