TRUNC function
Truncates a number while keeping a specified number of decimal digits.
This function is equivalent to the ROUNDDOWN function.
The rounding method used by this function is known as rounding towards zero. The resulting number will always be smaller than or equal to the original number.
TRUNC(Number [; Count])
Number: The number to be truncated.
Count: Optional parameter that defines the number of decimal places to be kept. The default value is 0 (zero).
Use negative values for Count to round the integer part of the original Number. For example, -1 will round down the first integer number before the decimal separator, -2 will round down the two integer numbers before the decimal separator, and so forth.
=TRUNC(21.89) returns 21. Note that this example uses the default value for Count which is 0.
=TRUNC(103.37,1) returns 103.3.
=TRUNC(0.664,2) returns 0.66.
=TRUNC(214.2,-1) returns 210. Note the negative value for Count, which causes the first integer value before the decimal separator to be rounded towards zero.