Pick a number less than 600 that is not
a perfect square (not the square of a whole number). Record this
Players take turns. At each turn a
Estimates the square root of the target
number and enters this estimate on the calculator.
Finds the square of the estimate with
the calculator and records it. (Use the [x2] key or
the multiplication key.)
The first player who makes an estimate
whose square is within 0.1 of the target number wins the game.
For example, if the target number is 139, the square of the estimate
must be greater than 138.9 and less than 139.1.
Note: The 
key on the calculator may not be used. This key provides the
best estimate of a square root that the calculator can calculate.