Create a variable where you need the indication, then use the following expression for that variable (important to note it might need tweaking depending on simplex/duplex and exact requirements/definitions etc.):
STR(INT(COUNTER(1,500,1/50))) & "." & STR(COUNTER(1,50))
One could alternatively replace the 1st counter statement by PAGE_NR()/50 or LAYOUT_NR()/50 (can use print preview to review the output, and use /100 if using duplex to account for the 2 pages per sheet for example).
In the above setup the 500 can be made larger to allow printing more pads before the 1st counter restarts at 1 etc.
Hope this helps, kind regards.