...
Where in.value contains [12.343,12.345], roundDown() returns [12.34, 12.34]
Whole Numbers
Use the decimalPlace -1 to round down to the nearest multiple of 10, and -2 to round down to the nearest multiple of 100.
roundDown(187, -1)
returns 180
roundDown(182282, -1)
returns 180280
roundDown(10187, -2)
returns 100