Carryless Arithmetic Mod 10

David Applegate, Marc LeBrun, N. J. A. Sloane

We investigate what arithmetic would look like if carry digits into other digit position were ignored, so that 9 + 4 = 3, 5 + 5 = 0, 9 X 4 = 6, 5 X 4 = 0, and so on. For example, t…