Hi with a ti-85 do : lbl a if 0=0 then goto a end After a few minutes you will have a memory error Ok, this is because the Ti-85 keep in memory at each iteration that there was an 'if'/'then' and no 'end'. Do the same thing on a ti-92 : lbl a if 0=0 then goto a endif I run that 10 minutes with no error ! How the ti-92 can do that ? Denis