The result number of a truncation approximation.
Example
The number 3.1415 is an approximation by truncation to the ten thousandth of the irrational number π while the number 3.1416 is a rounding to the nearest ten thousandths.
The number 3.1415 is an approximation by truncation to the ten thousandth of the irrational number π while the number 3.1416 is a rounding to the nearest ten thousandths.