Textbooks have included the occasional awful problem ever since Pebbles Flintstone and Bamm-Bamm Rubble chiseled their homework on slate tablets while attending Bedrock Elementary. But even with the understanding that there have been children have been doing awful homework problems since the dawn of time (and long before the advent of the Common Core), this one is a doozy.
There’s no sense having a debate about standards for elementary mathematics if textbook publishers can’t construct sentences that can be understood by students (or their parents).
On its face, problems 11 and 12 don’t look so bad. For #11, the appropriate inequality is
For #12, the inequality is
These indeed are the answers that the textbook is expecting. However, both answers are wrong because both and have to be positive. So the answers should be and . Which would be no big deal — except that these problems appeared before compound inequalities were introduced. (Notice that problems 7 through 10 only contain a single inequality.)
So, in a nutshell, the correct answers for these problems require skills that students have not yet learned at the time that they would attempt these problems.