Shortening numbers within the Mapper

Situation:

We've got a value with 4 decimal numbers like 39,8001. This should be shortened (not rounded) like these examples:

39,8000 should become 39,80
46.5760 should become 46.57

Format-number and round functions round decimal numbers to

39,80
46,58

This is not what should happen here.

A function like 'Floor' cuts everything behind the decimal character. Using this function it seems java uses a floating point.

Trying (Floor(input*100))/100, results in
39,79 (real input value *100= 3979,9999999999995)
46,57

Solution:

Using this as input value works: (Floor((input*100)+0,0000000000005)/100

Result:

39,80
46,57