Writing to Learn/Writing to Demonstrate Learning
Admit/Exit Slips Example 2

Which is greater, the sum of -219 and 327 or the sum of 219 and -327?  Explain.

Sample A
-219 + 327 is greater than 219 + -327 because 108 is more than -108.

Sample B
Neither one is greater.  The answers are the same because the numbers are the same.

Sample C
Because the numbers have different signs I have to subtract their absolute values.  The absolute values are the same, but because the larger absolute values are different for each problem, the first sum is greater.

Teacher Comments
This question is good after students have been working with addition of signed numbers for several days.  I am looking for students to recognize that the sign of the sum will be the same as the sign of the term with the larger absolute value.  Discussion of the responses provides a good review of the concept before moving on to the next lesson objective.  Both A and C are on target.  Student B needs more time with the concept.

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