HIGHLINE SCHOOL DISTRICT MATH OLYMPIAD March 25, 2000

Cell Phone Problem Scoring Guide

CORRECT ANSWER:

Points

Look for the following:

One or both of the following statements

· If Sally makes 84 or more calls per month she should choose the corporate plan.

· If Sally makes 83 or fewer calls per month she should choose the individual plan

· Answer is not correct.

PROBLEM UNDERSTANDING

What did you notice about patterns?

Points	Look for the following:
4	· Notices that for few calls individual plan is better than corporate · Noticed that Sally saves 30 cents on each corporate call but pays $25 extra per month. Recognizes that it is necessary to know how many 30 cent calls could be made for $25 to determine the cross-over point from individual to corporate.
3	· Notices that for few calls individual plan is better than corporate · Notices that for many calls corporate plan is better · Recognizes that the change for each additional call is constant
2	· Notices that for few calls individual plan is better than corporate · Notices that for many calls corporate plan is better · Did not extend the pattern any further
1	· The task is misunderstood
0	· No attempt at response.

STRATEGY

Students were asked: What strategy did you use?

Points	Look for the following:
4	· A valid strategy is used: use a rule, guess and check, make a table, write equations, draw a graph
3	· A valid strategy is used, but may have breakdown in logic.
2	· Strategy was applied , but steps may be missing · Labels may be missing or directions may not have completely been followed
1	· Strategy was not explained according to directions, or the reasoning is confused (but there was one)
0	· No attempted strategy, just answers

COMMUNICATION

Students were told: Explain your reasoning using sentences, pictures. or tables

Points	Look for the following:
4	· Described strategy and solution clearly and completely, step-by-step, with all steps included · Appropriate labels, terminology, and symbols are used
3	· Described strategy and solution, but steps may be missing from the explanation. The evaluator is required to infer that intermediate steps were performed correctly · Appropriate labels, terminology, and symbols are used
2	· Strategy was described, but steps may be missing or out of order
1	· Strategy was not explained according to directions, or reasoning is confusing
0	· No attempt to explain

REASONABLE RESULT

Student was asked: How do you know your answer was reasonable? Did you work the problem a different way?

Points	Look for the following:
4	· Review used a different approach to support the result · Review demonstrated correctness of work (showed work) · Explained why the result makes sense
3	· The result was checked using the same approach as initially
2	· A statement is make about checking the result without supporting information
1	· A check was done but it was not valid
0	· No attempt was made to demonstrate the reasonableness of the result