## Reflection: Unit Exams Unit Test - Section 2: Unit 2 Test

I evaluated the open response question A from the test and grouped them in the following way:

Novice:  This student said he disagreed with Marco, but said that Marco needed to change the nines to eights because of regrouping.  This is not correct.  This student fails to notice that Marco does not line up the place values correctly.  If he made an estimate he would see that 1199.03 does not make sense as the answer to 12.0001 - .98.  From this response, this student does not understand subtracting decimals and how to use estimates to check your work. Unit 2.15 ORQ A Novice.jpg

Approaching Mastery:  This student says that she disagrees with Marco because he put the decimal in the wrong place.  She also says that it was totally wrong for Marco to put a decimal in front of 98.  This student understands, at a basic level, that she needs to align place values in order to subtract them.  She comes up with an answer of 11.9903.  Her confusion is with the value of .98.  She doesn’t realize that .98 should be aligned under the tenths and hundredths place of 12.0001.  For some reason she instead aligns 98 under the thousandths and ten-thousandths place and does not include a decimal. Unit 2.15 ORQ A Approaching Mastery.jpg

Proficient:  This student disagrees with Marco because “he lined it up wrong”.  She rewrites the problem and correctly aligns .98 under 12.0001.  She regroups correctly and figures out that the actual answer is 11.0201.  It is clear that she understands how to subtract decimals.  This work is not advanced, because she fails to provide an in-depth explanation of why what Marco did was incorrect. Unit 2.15 ORQ A Proficient.jpg

Advanced: This student disagrees with Marco because he did not “set up the numbers correctly”.  He says that he could’ve put a zero [after] 98 hundredths because it will still have the same value”.  He understands that .98 and .9800 have the same value.  He rewrites the problem and finds the correct answer is 11.0201.  From this student’s work and explanation it is clear that he not only knows how to subtract decimals but he also understands why he must line up the place values. Unit 2.15 ORQ A Advanced.jpg

Unit Exams: Student Work: Open Response Question A

# Unit Test

Unit 2: The College Project - Working with Decimals
Lesson 16 of 16

## Big Idea: What have students learned during this unit? What gaps do students have in their understanding? Students take the Unit 2 test.

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Standards:
Subject(s):
Math, Fractions, Number Sense and Operations, Decimals, addition, subtraction, division, multiplication, percent, 6th grade, master teacher project
60 minutes

### Andrea Palmer

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