In practice you wouldn’t be able to mine at all, because the difficulty updates infrequently, so you would have to mine several blocks at the old difficulty. Ob

In practice you wouldn’t be able to mine at all, because the difficulty updates infrequently, so you would have to mine several blocks at the old difficulty. Obviously this is impossible on a pocket calculator. I’ve always assumed that the notion of longest chain takes difficulty into account, although I haven’t really been able to find confirmation of this.