Luke wnats to play the 4 number game with the number 1,2,3 and 4 and the operations of addition, multiplication, and subtraction.
Leoni responds, “or we just could play the 4 number game with just the operation of addition and multiplication, but now with the number -1, -2, -3, -4, 1, 2, 3, and instead.”
What observation is leoni trying to point out to Luke ?