I’ve done away with the Did You Pass Math plugin (at least temporarily) so that people can comment without having to compute. Instead, I’m trying on Spam Karma 2. My worry is that Spam Karma will produce too many false positives; that is, labeling legitimate comments as spam. I did not have the worry of false positives with Did You Pass Math but I fear that false negatives were too frustrating to readers. I just wish Spammers would go away.