[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