When I was in grade school, math textbooks had answers in the back of the book. But they didn’t have all the answers — just the answers to odd-numbered questions.

So when a teacher assigned the “evens” for homework (and they always assigned the evens) you couldn’t copy answers, and you couldn’t check your answers either. Even if you did the work honestly, you couldn’t find rock-solid evidence that you’d done things exactly right.

The only option was to do your best and to trust yourself … and occasionally to check with a friend for the most difficult questions. (Right or wrong, maybe you two had solved it the same way.)

It turns out, much of life is like getting the even-numbered questions for homework.