Description
Darts is a Microworlds activity that requires the player to pop a balloon that appears on a number line between 0 and 1 by throwing fractional darts.

Setting the Stage
Play this decimal game with the students. "I'm thinking of a decimal between 0 and 1.  Can you guess it?  (Choose .75 as your fraction to guess.)  A student may guess .5. You would say that his or her number is too small. Another student may say .8 to which you respond with that's too big. The next guess could be .7 which elicits a too small response. At this point the students may realize that they need to a decimal fraction that is between .7 and .8. Some students may need help in realizing that a number like .75 is in between and would guess correctly. At this point show them the challenge problem and explain how Darts works. 

Playing Deci Darts
Hand out the student page and ask the students to explain mathematically how they found a number between .75 and .625.  Some possible anwers would include:

• .7. I compared the numbers .750 and .625 and saw that .700 is in between .750 and .625. I entered .7 since it is a simpler form of .700.
• .683. Since the difference between .750 and .625 is .125 I added half of that (approximately .063) to .625 and this gave me a number that is almost half way between .625 and .750. . 
  
   Play a round of 5.
    Name:

Note: DeciDarts.mw2 will be available in Java format on the web at Decidarts student page. Permission for using the program is granted by Robert Berkman who holds the copyright for the fractional version.