FLOOR.MATH
Category: Mathematical Function.
Description: Rounds a number down, to the nearest integer or to the nearest multiple of significance.
Syntax: FLOOR.MATH(number, significance, mode)
The number is the value to round, the optional significance is the multiple to which you want to round, the optional mode specifies the direction to round negative numbers (toward 0 if equal to 0, away from 0 if the mode is not zero).