I'm a relatively new user of Maple, and I use it to teach high school mathematics. I've noticed that when Maple expands an expression like (x+y+z)^6, the terms come out in a different order each time the operation is done. If 6 students do it on 6 computers we get 6 different orderings. Is there an explanation for why Maple's algorithm does this that would be potentially comprehensible to my students (they are quite curious)?