How do you have 15 take away 6 and have 10 left?

Answer 1

Well, that would be true if the first two numbers are in base=11

but the 10 is in base=10.

(15)11 = decimal 16

(6)11 = decimal 6

(15)11 - (6)11 = (decimal 16) minus (decimal 6) = decimal 10

(*For the solution to the Poptropica riddle, see the related question below.)