




Massachusetts Comprehensive Assessment System
2011, Grade 8 Mathematics
Question 21: OpenResponse 

Reporting Category: Number Sense and Operations Standard: 8.N.12  Select and use appropriate operations—addition, subtraction, multiplication, division, and positive integer exponents—to solve problems with rational numbers (including negatives). 
Leo works 22.5 hours each week and earns $9.48 per hour. What amount of money does Leo earn each week? Show or explain how you got your answer.
Each week, $25.60 is taken out of Leo’s earnings for taxes. What percent of Leo’s weekly earnings is taken out for taxes? Show or explain how you got your answer.
 Leo wants to buy a car that costs $3000. He plans to save all of his earnings that remain after taxes are taken out. What is the minimum number of hours that Leo must work in order to save $3000 to buy the car? Show or explain how you got your answer.

Scoring Guide and Sample Student Work Select a score point in the table below to view the sample student response.
Score  Description 
4 
The student response demonstrates an exemplary understanding of the Number Sense and Operations concepts involved in selecting and using appropriate operations to solve problems with rational numbers. The student works with decimals and percents to solve a multistep, realworld problem. 
4 
3 
The student response demonstrates a good understanding of the Number Sense and Operations concepts involved in selecting and using appropriate operations to solve problems with rational numbers. Although there is significant evidence that the student was able to recognize and apply the concepts involved, some aspect of the response is flawed. As a result the response merits 3 points. 
2 
The student response demonstrates fair understanding of the Number Sense and Operations concepts involved in selecting and using appropriate operations to solve problems with rational numbers. While some aspects of the task are completed correctly, others are not. The mixed evidence provided by the student merits 2 points. 
1 
The student response demonstrates only minimal understanding of the Number Sense and Operations concepts involved in selecting and using appropriate operations to solve problems with rational numbers. 
0 
The student response contains insufficient evidence of an understanding of the Number Sense and Operations concepts involved in selecting and using appropriate operations to solve problems with rational numbers to merit any points. 
Note: There are 2 sample student responses for Score Point 4.
Grade 8 Mathematics
 Question 9: Patterns, Relations, and Algebra
 Question 21: Number Sense and Operations
Return to the MCAS 2011 Student Work Directory
Last Updated: May 19, 2017


