What you could do is the following:
1) Create a number field with 2 decimals. The result will be less than 9.
2) Consequently convert the number to a text by using the function “combine A with B”. (A= number from step 4, B = empty text)
3) Calculate the number of characters minus number of decimals and comma in a calculation (so, in the case of two decimals (-2 + -1 = -3) )
4)Use the function “Cut A from B for n characters”. A = new textfield, B=1, n= Calculate the number of characters minus number of decimals and comma.
5) Create a new textfield in your datamodel and save there the outcome of step 4.
Will this help?