Ronald Reagan guessed wrong. David Stockman guessed wrong. But Joan and Gary Kuiper of Alexandria were right on the money--and beat out thousands of other Washington Post readers to win The Federal Report's Trillion-Dollar Forecast competition.

Gary Kuiper, a lawyer with the Washington firm of Watt, Tieder, Killian, Toole and Hoffar, and his wife, Joan, a waitress at the Boar's Head restaurant in Falls Church, won the prize by forecasting the day the national debt would top $1 trillion--Oct. 22--and by coming within $14 million of predicting how large the debt would be at the end of that day. (The closing total was $1,000,878,000,000.)

President Reagan said on Sept. 24 that the trillion-dollar mark would come "in a few days." Budget Director Stockman made an off-the-cuff prediction of Oct. 12. But the Kuipers were not misled. They called the Treasury Department--"I was transferred to about 12 different people," Gary Kuiper said--to learn about the debt, and then submitted a batch of entries covering many possible winning combinations.

The economic savants will be rewarded with lunch on The Washington Post and some minimally valuable prizes.

While the Kuipers had the most accurate entry of all, more than 100 Post readers correctly predicted the trillion-dollar day. Those who hit the day were:

Louis Alexander, Washington; Chuck Angelucci, Richmond; Abraham Anson, Falls Church; Alejandro Becerra, Falls Church; Bruce Berman, Bethesda; Howard L. Blum, Kensington; Robert L. Bowers, Vienna; Robert Brady, Bethesda; Ann Buchynsky, Rockville; E.J. Burke, Cedar Knolls, N.J.; Arthur F. Carley, Aspen Hill; Robert Chadwick, Washington; John C. Clark, Hilton Head, S.C.; Robert W. Conway, Alexandria; Shirley Croson, Dumfries; Ann Czupryn, Alexandria; Glenn A. Dallaire, Arlington; Arthur Day, Alexandria; Renee Domogauer, College Park; John M. Duvall, Waldorf; Julie Dzikowski, Charlottesville.

Paula T. Fleming, Stamford, Conn.; Jacob T. Forbai, Washington; Stephenie Foster, Washington; Calvin H. George, Silver Spring; Jack Ginsburg, Springfield; Richard A. Goldman, Dumfries; Calestard Gravett, Forestville; Peter Greene, Washington; Richard F. Grimmett, Silver Spring; James M. Guiliano, Annandale; Janet Halshyn, Arlington; Joseph M.S. Haraburda, Falls Church; Lindsey B. Herd Jr., Falls Church; Daniel Hillstrom, Gaithersburg; Anna P. Jones, Greenbelt; Wayne Jones, Washington; Brian F. Kelly, Washington; Shaun Kirchoff, Washington; Scott D. Krueger, Falls Church.

R. I. Levine, Washington; Herb Lewis, Columbia; George J. Livieratos, Columbia; Dan Mayeda, Washington; V. J. McGrath, Woodbridge; Willie J. McKnight, Washington; Mark T. McMullen, Springfield; Lynnwood Minar, Herndon; A.E. Moakler, Washington; Jack Richard Moore, Merritt Island, Fla.; Marjorie Moore, Washington; John Morse, Washington; Robert Nehmad, Falls Church; M. Suzanne Nettles, Bowie.

Harry Obst, Annandale; Rita E. Oliver, Alexandria; Paul Oyer, Alexandria; George T. Ozaki, Kensington; Dale S. Pearson, Washington; Maureen Pearson, Washington; Sue Peterson, Charlottesville; Bob Pianowski, College Park; Herbert Press, Columbia; Susan Quinlan, Alexandria; Charles W. Rahn, Washington; Shirley Reid, Washington; Elizabeth A. Roub, Washington; Lynwood T. Rowe, Washington.

Robert O. Santos, Manassas; Ed Schwartz, Falls Church; H.D. Servis, Ft. Washington, Md.; Thomas D. Shambaugh, Washington; K.H. Shankar, Woodbridge; Peg Shaw, Washington; Rasika Shetty, Rockville; Anne Shipman, Washington; Nicholas Shwaery, Alexandria; E.D. Stalder, Springfield; W.W. Tipton, Kensington; Brian Thoreson, Washington; LaVerne Tinsley, Ft. Washington; Edward L. Turner Jr., Arlington.

Maxine Upshur, Fairmont Heights, Md.; Michael G. Van Dress, Arlington; Karla Berg Walker, Silver Spring; Don Wang, Washington; William Warren, Alexandria; Alan Wetherbee, Washington; Frederick E. Webb, Falls Church; Ruth White, Hillcrest Heights; George B. Wilkinson, Charleston, W.Va.; Judith Willis, Arlington; T. Michael Wrabell Jr., Dumfries; Henry Woods, Falls Church; Shannon Yates, Alexandria; Isadore Zisman, Washington. CAPTION: Picture, Gary and Joan Kuiper were right on the money - or at least on $14 million off. By Joel Richardson; The Washington Post