Setting threshold to assign real values to class values

Hello folks. I am doing a data mining regression exercise and after getting prediction results which are real values, (e.g. 5.78137) i need to assign these to class values (e.g. 5 or 6 depending on the threshold value I use). I am trying to do this in excel and would logically think that the formula would be something like this: =IF(M2>"*.4","*+1","*"). This obviously isn't the formula but i thought including it here could help convey what i'm trying to do. The * in the formula represents the 5 in the 5.78137. Does anyone have any ideas on how exactly you assign real values to class values based on a threshold value e.g. 0.4.

Thanks in advance.

Barry.

Look at formula in column B in the attached file. Is this what you where looking for?
You can change the treshold value in cell B1.
Pierre