Getting Started 
Misconception/Error The student does not have an effective overall strategy for solving the multistep problem. 
Examples of Student Work at this Level The student:
 Correctly calculates the clothing cost of $261 but does not take into account the tax.
 Calculates the clothing cost correctly (or incorrectly) but does not know how to calculate tax and/or what to do with it.
 Attempts some calculations with values given in the problem not related to the problem solution.

Questions Eliciting Thinking What is your overall strategy for solving this problem? What questions must be answered?
What have you done so far? Where would you go from here?
I see that you calculated $261. What does that represent? What else is needed?
What is sales tax? When you purchase something, how is the sales tax taken into account? 
Instructional Implications Assist the student in developing an overall strategy for solving problems involving purchases and tax. For example, guide the student to first find the subtotal of item costs, next calculate the tax, then find the total purchase price, and finally compare the total cost to the amount of money available.
Give the student opportunities to solve similar types of problems but with “easier/smaller” numbers, allowing the student to focus on developing a general strategy for solving the problem. Provide feedback as needed.
Help the student understand tax, sales, discount, commission, and interest and distinguish among those that increase the cost and those that decrease the cost. Discuss with the student the difference between “sales tax” and “sale price.” 
Moving Forward 
Misconception/Error The student determines an effective overall strategy for the problem, but is unable to correctly calculate the dollar amount of the tax. 
Examples of Student Work at this Level The student:
 Simply adds $6.50 to the cost of the clothing, misinterpreting the tax rate as a dollar amount of tax.
 Correctly finds the cost of the clothes, but then attempts to multiply the cost, $261, by 6.5.
 Divides the subtotal (261) by the tax rate (6.5) to get a tax of $40.15.
 Indicates that he or she does not understand how to calculate the dollar amount of the tax.

Questions Eliciting Thinking Is the amount of the tax given to you in the problem or is it something you have to calculate?
How is the number different than % and $6.50? What does it mean to describe the tax with a percent?
Is it possible for the tax to be more than the cost of the items – does your answer make sense?
Why did you divide the purchase price by 6.5? What does the 6.5 represent? Is that the same as 6.5%? 
Instructional Implications Review the meaning of percent and how to calculate the percent of a quantity using proportional reasoning. Emphasize the relationship between a percent and its ratio equivalent. Provide problems that include rational number percentages as well as whole number percentages. Emphasize the differences among writing 60%, 6%, and 0.6% as fractions or ratios.
Review the meaning of tax with the student, the role tax plays in calculating the total cost of a purchase, and that tax is generally given as a percent. Provide additional opportunities for the student to solve problems that involve calculating tax given as a percent. 
Almost There 
Misconception/Error The student makes a minor mathematical error or shows work in a mathematically incorrect way. 
Examples of Student Work at this Level The student:
 Makes a rounding error in calculating the tax.
 Calculates a subtotal based on buying three shirts but only one pair of jeans. All other work is correct.
 Provides a correct answer but without sufficient supporting work.
 Appears to have made correct calculations using a calculator but writes an equation to represent the work as $261 + 6.5% = 277.965.

Questions Eliciting Thinking Can you check your multiplication (addition/subtraction) again to see if you have any errors?
What does the answer 16.965 mean as the tax? When working with dollars and cents, to what place value are numbers rounded?
Can you explain to me what this math statement means? How did you arrive at your answer? Can you add dollars with percentages? What would the units of the answer be? What would be a better way to write this statement?
I see your math calculations but not an answer to the question. How can you determine if she has enough money? 
Instructional Implications Encourage the student to review his or her work and to consider the reasonableness of answers. Provide the student with additional problems that involve discounts, interest, gratuities, and commissions. Have the student work with a partner to compare work and reconcile any differences.
Guide the student to correctly write mathematical expressions and equations. Distinguish between the sequence of keystrokes needed to enter a problem into the calculator and the way that mathematics is written. Have the student explain any written mathematical statements using appropriate terminology. 
Got It 
Misconception/Error The student provides complete and correct responses to all components of the task. 
Examples of Student Work at this Level The student calculates a total clothing cost of $261 and a tax of $16.97 for a total purchase price of $277.97. The student is able to explain that there will not be enough money for the purchase and can determine that Tiffany will be short of money by $2.97. All steps, calculations, answers, and explanations are correct and clearly stated.

Questions Eliciting Thinking What change will she have to make to her purchase in order to keep her total within the amount of money she has available? What will her total purchase price be with that change?
If the tax rate was 6% instead of 6.5%, would she have had enough money?
If her final total came to exactly $275, how would you determine what tax rate she was charged?
How is the tax rate determined? Is it the same for everyone and in every store? 
Instructional Implications Have the student solve other multistep problems involving discounts, interest, gratuities, and commissions.
Explore with the student what percent increase and percent decrease mean and how they are calculated. 