NARRATOR: OK Fin, you want to take away 6 from 12 by counting back through 10 as well. 12 minus 2 equals 10, so to get 10, just take 2 of the 6 shells away. That leaves you with 4 shells to take away.

What an interesting shop. NARRATOR: That’s a good idea, Fin. Arrange your credits into stacks of 10 to make them easier to count. 1 stack of 10… 2 stacks of 10. That leaves 4 credits left over.