Editing Truncation (section)

== Truncation and floor function ==
{{main|Floor and ceiling functions}}
Truncation of positive real numbers can be done using the [[floor function]]. Given a number <math>x \in \mathbb{R}_+</math> to be truncated and <math>n \in \mathbb{N}_0</math>, the number of elements to be kept behind the decimal point, the truncated value of x is
:<math>\operatorname{trunc}(x,n) = \frac{\lfloor 10^n \cdot x \rfloor}{10^n}.</math>

However, for negative numbers truncation does not round in the same direction as the floor function: truncation always rounds toward zero, the <math> \operatorname{floor} </math> function rounds towards negative infinity. For a given number <math>x \in \mathbb{R}_-</math>, the function <math> \operatorname{ceil} </math> is used instead
:<math>\operatorname{trunc}(x,n) = \frac{\lceil 10^n \cdot x \rceil}{10^n}</math>.