3.NF.A.3d Comparing Fractions
Evidence Statement 3.C.4-4 Distinguish correct explanation/reasoning from that which is flawed, and if there is a flaw in the argument, present correct reasoning. (For example., some flawed student reasoning is presented and the task is to correct and improve it.)
Rosina was explaining how to compare 2/6 and 3/6 her friend. She drew the rectangles below to help her explain.
This image shows a large rectangle partitioned into 6 equal parts with 2 parts shaded and a small rectangle partitioned into 6 parts with 3 parts shaded.
Rosina tells her friend that 2/6 > 3/6.
- Explain why Rosina’s thinking is incorrect.
- Explain how to correct Rosina’s thinking.
- Write the correct comparison for 2/6 and 3/6 using < or >.
Enter your explanation and answer below.
Student response includes the following 2 elements.
- Reasoning component = 2 points
- The student explains that Rosina did not compare the fractions correctly because the rectangles were not the same size.
- The student explains that in order to compare fractions the wholes must be equal.
- Computation component = 1 point
- The student provides the comparison, 2/6 < 3/6.
Student response includes 2 of the above elements.
Student response includes 1 of the above elements.
Student response is incorrect or irrelevant.