FLOOR

FLOOR(number, significance)

Returns the number rounded down to the nearest integer or significant figure.

number	The number to be rounded down.
significance	The multiple you want the number rounded to.

REMARKS

* FLOOR.MATH was added in Excel 2013 to replace this function.
* If any of the arguments are not numeric, then #VALUE! is returned.
* If "number" or "significance" have different signs, then #NUM! is returned (last example ?)
* Regardless of the sign of number, a value is rounded down when adjusted away from zero. If number is an exact multiple of significance, no rounding occurs.
* For the Microsoft documentation refer to support.microsoft.com

	A
1	=FLOOR(2.5,1) = 2
2	=FLOOR(-2.5,-2) = -2
3	=FLOOR(1.5,0.1) = 1.5
4	=FLOOR(0.234,0.01) = 0.23
5	=FLOOR(28.4,0.5) = 28
6	=FLOOR(12.2,0.5) = 12
7	=FLOOR(28.4,0.1) = 28.4
8	=FLOOR(-2.5,2) = -4