Cetin:

>>>>>>>>>>

for ix=1 to alen(arrNums)-1
   if arrNums[ix]+arrNums[ix+1] = X
      ? ix,ix+1,arrNums[ix],arrNums[ix+1]
   endif
endfor

>>>>>>>>>>
This only works if the two numbers are adjacent in the array (which is not the case in general).

> Just chained to draw attention to my real world puzzle in troubleshooting
> section :)
I actually used the winning algorithm twice in production systems: (1) a portfolio management system for an insurance company, (2) a resource utilization system for a lumber company.

Daniel