## Archive for January 9, 2013

### Math Dreams

“I can’t get the numbers to stop.”

That’s what Eli told my wife tonight when he woke from a bad dream.

I once had a dream where I was afraid of numbers, too. During the week leading up to my midterm in Linear Algebra, I was reviewing problems from old exams. Though I thoroughly understood all that had been covered in class, and though I was able to complete all the exercises from the textbook with aplomb, I was only getting about 25% of the questions on the old exams correct.

It was freaking me out, and the night before the exam, I went to sleep very nervous.

My sleep was broken by a nightmare in which numbers were flying past my head like cannonballs from a numerical howitzer. They were coming from every direction. To make matters worse, my head was being squeezed by the brackets of a matrix as if it were in a vice.

I woke in a cold sweat. It was 5 a.m. Too anxious to sleep any more, I went to a study carrel in the library where I read and re-read the textbook and continually tried the problems from the old exams. I skipped my morning classes and studied for five straight hours. Yet I was still only able to get a quarter of the problems correct.

The midterm was at 12:30 p.m. At 11:55 a.m., I saw a woman from my class. Though I had never spoken to her before, I approached her and said, “Excuse me, aren’t you in Dr. Sibley’s linear algebra course?”

“Yes,” she replied skeptically.

“Would you mind helping me?” I asked, embarassed by the question.

“Uh… sure,” she said.

I asked her a few questions about the topics we had covered. She confirmed that I understood the material correctly. “So why am I missing so many of the questions from the old exams?” I asked rhetorically.

She took a look at my work and confirmed that it, too, was correct. Then she revealed the punch line: The professor had given us a packet of six exams, and the answer keys for all six exams were copied onto a seventh sheet. But the answer keys and the exams were **not** in the same order — each answer key had to be matched to an exam by noting the semester and date on each.

Arrgh.

I was relieved. Yet frustrated. I managed an 85 on the midterm… yet I’m certain I would have aced it had I gotten a good night’s sleep.

Mark Jason Dominus has much better math dreams than I. He posted the following problem to the mattababy listserv. He claimed that it came to him in a dream; when he woke, he thought it was still a good problem, so he decided to share it.

The volume of a 3 × 3 × 3 cube is 27 cubic units, and the volume of a 2 × 2 × 1 prism is 4 cubic units. Theoretically, six prisms should be able to fit inside the cube, with three cubic units empty. But can you arrange six 2 × 2 × 1 prisms so they fit inside a 3 × 3 × 3 cube?

Friends of mine who taught at the Center for Talented Youth claim that M. J. Dominus would often arrive late to the evening study sessions. As the story goes, he would take naps after dinner… if his alarm sounded while he was in the middle of a math dream, he would shut off the alarm and return to sleep so he could finish whatever mathematical proof his subconscience had been working on.

Wow.

**What’s the scariest or coolest math dream you’ve ever had?**