Think you're doing the exact same as me but I started from the right. 1-0+1-7+8-6. This way you end up with the remainder mod 11, if you start from the left you

Think you're doing the exact same as me but I started from the right. 1-0+1-7+8-6. This way you end up with the remainder mod 11, if you start from the left you sometimes need to flip the sign at the end.