I friend of mine assists in the Santa Cruz CA public schools. She reports that a teacher told the class that officially 1 is a prime number, while admitting that mathematicians think otherwise. Bill, since your friend was hauled before the "dean" rather than the "principal", I'm guessing he goes to a private school. That doesn't bode well for the quality of that private school. -- Gene From: Bill Gosper <billgosper@gmail.com> To: math-fun@mailman.xmission.com Sent: Thursday, December 10, 2015 3:50 AM Subject: [math-fun] Mixed numbers? A young friend has to convert all his "improper" fractions to mixed numbers. When he repeated my remark that mathematicians, scientists, and engineers shun mixed numbers, he got hauled up before the dean, who angrily insisted that mathematicians actually prefer mixed numbers. Does anybody know a computer algebra system that even offers mixed numbers as an output format? An input format?? --rwg A still younger friend emailed: What?? 3½=3+½?? That's crazy! I was showing this guy rotation matrices, and he seriously asked, "What's a degree? Is that like pi/180?" --rwg _______________________________________________