Happy New Year's Challenge

The year 1999 is approaching, and we have a challenge for you! Use the digits in the new year (1, 9, 9, and 9) once-and only once-to write a series of equations in which the results equal 0 to 10. You may add, subtract, multiply, divide, use exponential forms, and/or use square roots.

Here is how you might begin:

(9 - 9) ? 9 ? 1 = 1

????????????? = 2

????????????? = 3

????????????? = 4

????????????? = 5

????????????? = 6

????????????? = 7

????????????? = 8

????????????? = 9

????????????? = 10

Can you do this without using a square root?

Can you go on to 20? Don't forget the Order of Operations!

Send your answer to Laura Blackburn, Math Muse, c/o Northern Illinois University, EPCSE Department, Graham Hall 143, DeKalb, IL 60115. For questions or comments, contact Laura, lblackburn@niu.edu, or Claudia, pagliaro+@pitt.edu, through e-mail. Students who send in the correct answer will: Get their names published in World Around You. Win a Math Muse certificate. Win a free subscription to World Around You.