WORTH NOTING ON TV

WEDNESDAY

Living and Working in Space: The Countdown Has Begun (PBS, 8-9 p.m.): Tell kids they have to study math because "it's important" and watch some of them run the other way. Convince them that in future years they could be working in a space station or on Mars - environments where knowing math is the only way to survive - and you may get their attention. To make such a future real to kids is one purpose of this celebrity-filled special. Going behind the scenes for interviews with space officials, it explore s careers in space, where you have to know math because you live, breathe, and talk the subject all day. The well-chosen host is Jaime Escalante, who played the embattled math teacher in the film "Stand and Deliver" and recently hosted another PBS special called "Math ... Who Needs It." Although essentially a documentary, this show uses reenactments to add punch to the facts.

A Practical Guide to the Universe (The Learning Channel, 8:30-9 p.m.): Time travel, the asteroids, how the world started - all are grist for the weekly 10-part science series premiering here. The programs provide answers about the universe of interest to a range of ages - including pre-schoolers, who are more likely to ask basic questions than others. The host is Tom Selleck, not so strange a choice when you think about the philosophical skepticism and questioning attitude that seemed to lurk beneath his

maverick personality on his network TV series, "Magnum, P.I." So quarks, galaxies, and the possibility of life on other planets come more naturally to him than you may think. The series begins, logically enough, with "The Beginning of Time." FRIDAY

Time Machine With Jack Perkins (Arts & Entertainment network, 5-8:30 p.m.): The 1982 British campaign to regain the Falkland Islands, after Argentina invaded them, was skillfully waged against heavy odds. Behind the action, though, unheeded warnings and political struggles in London may reveal a less glorious tale. "The Falkland Wars" offers an examination of this dramatic and intensely covered period of recent history.

Please check local listings for all programs.especially on PBS.