The Witch´s One-Time-One!

If you´re a regular visitor of my blog, you won´t be surprised to see verses from Goethe´s "Faust" as my entry for this week´s SPA challenge themed "Witches". I imagine the man on the right could be Goethe himself, reading from his drama, but maybe it´s just a second witch or a magician ... I can´t tell! But here´s the spell:

"This you must ken! From one make ten, and two let be, make even three, then rich you´ll be. Skip o´er the four! From five to six, the witch´s tricks, make seven and eight, ´tis finished straight; and nine is one, and ten is none, that is the witch´s one-time-one!"

(This translation is very close to the German original: "Du mußt versteh´n, aus Eins mach Zehn. Die Zwei laß geh´n und Drei mach gleich, so bist du reich. Verlier die Vier! Aus Fünf und Sechs, so sagt die Hex, mach Sieben und Acht, so ist´s vollbracht: Und Neun ist Eins, und Zehn ist keins. Das ist das Hexen-Einmaleins!")