how to display thevalue of variable 'XYZ' to screen o/p field in module pool

Hi guru,

i have one requiremnt in module pool as explain below.

1.i have one screen say '0120'.

2.it has three tabs A,B,C.

3.At tab B we have one subscreen which has three fields 'X',Y,,Z.

4.Fields 'X  and Z are coming from database table from 'ztable', which is input enabled .when user enters value in .X and Z  and save then ZTABLE will get update with value entered.

5.now we have 'Y' field for which value need to be displayed like below shown

               if X =5 ,Z =10

THEN   Y  SHOULD BE LIKE      ' >5 <= 10'

i have declared two variable g1 and g2 for two values and moving the values g1 = 5 and g2 = 10 in PBO of screen 0120.it works fine.and the same variable i have given in screen attributes for Y also.when o/p is displaying the value of Y IS NOT DISPLAYED .

please help me.