10 LET n=5: GO SUB 1000: PRINT s$
20 LET n=50: GO SUB 1000: PRINT s$
30 LET n=9000: GO SUB 1000: PRINT s$
999 STOP
1000 REM convert to binary
1010 LET t=n: REM temporary variable
1020 LET s$="": REM this will contain our binary digits
1030 LET sf=0: REM output has not started yet
1040 FOR l=126 TO 0 STEP -1
1050 LET d$="0": REM assume next digit is zero
1060 IF t>=(2^l) THEN LET d$="1": LET t=t-(2^l): LET sf=1
1070 IF (sf <> 0) THEN LET s$=s$+d$
1080 NEXT l
1090 RETURN