the first decimal place past the precision will be rounded up if greater than or equal to the rounding digit; this corresponds to the OMG round-up rule. When the rounding digit is 5, the result will be the one closest to the original number, hence the name.
all decimal places past the precision will be truncated
positive numbers will be rounded up and negative numbers will be rounded down using the OMG round up and round down rules
do not round: return the number unmodified
the first decimal place past the precision will be rounded up. This differs from the OMG rule which rounds up only if the decimal to be rounded is greater than or equal to the rounding digit
positive numbers will be rounded down and negative numbers will be rounded up using the OMG round up and round down rules