Here's an answer from some of my fourth graders:
Here's the lesson:
I walked in to class and told the kids that I had been walking down the street and found scraps of kids' subtraction work. I smiled. They asked if I was lying, and I lied and said that I wasn't. Then I said, also I found the original problem. They thought this shtick was pretty ridiculous. Anyway, I gave them this:
They did this:
Ben Blum-Smith wants us to name our problem-writing techniques, so I'll file this one under "hide the math."
[The source for those pictures was this really great NCTM article, by the way.]