2.NBT.A.1 Flawed Reasoning Place Value Remix

2.NBT.A.1 Flawed Reasoning Place Value

Evidence Statement 3.C.4-7  Distinguish correct explanation/reasoning from that which is flawed, and if there is a flaw in the argument, present corrected reasoning. (For example, some flawed student reasoning is presented and the task is to correct or improve it.)  Content Scope 2. NBT (for grade 3 this is previous knowledge from grade 2)

Ribbon Count

The table below shows the number of ribbons a swim team earned during their swim season.

Swim Team Ribbon Count

Part A

Jasleen says the team won 619 because 3+2+1=6, and 4+6+9=19.

Jasleen is incorrect in her reasoning.

• Explain why Jasleen is incorrect in her thinking.
• Write an equation or equations to find the correct total number of ribbons the swim team earned.

Enter your explanation and equation or equations in the space provided.

Part B

Jasleen says the team won 25 less third place ribbons then first place ribbons because 3-1=2

and 9-4=5. .

Jasleen is incorrect in her reasoning.

• Explain why Jasleen is incorrect in her thinking.
• Write an equation or equations to find how many less third place ribbons were earned than first place ribbons.

Write your explanation and equation or equations in the space provided.

Scoring Rubric Part A

Score 2 Student response includes the following 2 elements.

• Computation component = 1 point

o   The student provides the correct number of ribbons earned, 79 ribbons.

• Reasoning component = 1 point

o   The student explains that Jasleen did not use place value correctly.

• Notes:  If a computation mistake is made, credit cannot be given for the computation component, but 1 point can be given for a valid explanation.

Score 1 Student response include 1 of the above elements.

Score 0 Student response is incorrect or irrelevant.

Scoring Rubric Part B

Score 2 Student response includes the following 2 elements.

•  Computation component = 1 point

o   The student correctly provides how many less third place ribbons were earned, 15 ribbons.

• Reasoning component = 1 point

o   The student explains that Jasleen did not use place value correctly.

• Notes:  If a computation mistake is made, credit cannot be given for the computation component, but 1 point can be given for a valid explanation.

Score 1 Student response include 1 of the above elements.

Score 0 Student response is incorrect or irrelevant.