SmileBASIC can't save a single number, but rather only arrays. To save this number, you have a couple of options. You can save with SAVE "TXT:TEST",STR$(SUB) and load it with LOAD "TXT:TEST",FALSE OUT S$:SUB=VAL(S$) You can save with DIM ARR[1]:ARR[0]=SUB:SAVE "DAT:TEST",ARR and load with DIM ARR[1]:LOAD "DAT:TEST",FALSE OUT ARR:SUB=ARR[0]