Comment by civility

I think I see where you're hung up. If I change it to:

    x = 1e20 + 1 - 1e20
    y = 1e20 - 1e20 + 1
    assert x == y

There is only 1 digit, and it's wrong. You don't even need 6-8. I probably should've used this as my example in the first place.