10 REM Digital root
20 FOR I=0 TO 6
30 READ A
40 N=A:B=10:GOSUB 500
50 PRINT SPC(7-LEN(STR$(A)));A;PERS;ROOT
60 NEXT I
70 DATA 1,14,267,8128,39390,588225,627615
80 END
490 REM ** Calculate digital root
495 REM    and persistance
500 PERS=0
510 IF N<B THEN 590
520 S=0
530 S=S+N-INT(N/B)*B
540 N=INT(N/B)
550 IF N>0 THEN 530
560 PERS=PERS+1
570 N=S
580 GOTO 510
590 ROOT=N
600 RETURN