Sample A
I know that  you have to subtract the higher number on top or lower number on the bottom.
Ex. 20 - 10 = 10
I also know you can subtract like 4 - 5 you would have to swap the numbers 5 - 4 and adding you have to carry your number if it's higher than  9.
Ex. 13 + 9 = 22

Sample B
I know that two terms with the same variable are called like terms (Example:  5D and 16d) and I know that using the distributive property can be helpful in simplifying expressions that have like terms.
796p + 2002p = (796 + 2002)p = 2798p

Sample C
Subtracting and addition is easy.  I know how to do all subtracting and addition.

Sample D
Addimg and subtraction is two of the easiest type of math.  Adding terms is where you find the term that has the larger exponent and then that is the degree,  Subtraction is where you take one number and take that amount out of another number.

Sample E
I forgot how to, but there are a cuple of steps that I remember, but not much.  Add, multiply, subtract, divide.

Sample F
Adding is subtracting terms is whe a number, a variable, or a product of numbers and variables have plus and minus signs.  You can only add and subtract terms that have the same letters.

Sample G
What I know about adding terms is that like if you have a value of 5. And you add 3 to that value you would get the value of 5 increased 3 times so it would be 8.  What I know about subtracting is that the number your subtracting from the other number alwas has to come second.  This is all I know.

Sample H
I no when you add terms you do parentheses first and then multiplication.

Teacher Comments
This exit slip was used after students completed there test over an extended unit on geometry.  I was looking for some mention of the concept of like terms and wanted to assess how much review would be required.  It had been several months since this concept was discussed or actively used in the class.  These responses came from a collaborative pre-algebra class with about 2/3 ECE students.  This particular group needed frequent review and practice because retention of concepts when presented with abstract references tended to be extremely short term.  These responses were a non-threatening way to discover the students current recognition of the terms and concepts. The students knew they could answer honestly without penalty or embarrassment.  For most students the concepts of addition and subtraction were fairly clear although sample A evidences confusion about operations with signed numbers.  Samples E and H seemed to think the question refered to the order of operations.

With this particular class, instead of reading and discussing individual responses, the responses were used to restructure my plans for the unit.  Based on the majority of student responses, I determined that the best course of action for this class was to put together several cooperative lab activities on adding and subtracting like terms similar to what the students had completed earlier in the year.  Students were divided into cooperative groups and given manipulatives (algebra tiles) and a list of 10 expressions to simplify.  The variables in any single expression had the same power.  Student recognition of the activity and the process was immediate.  After each group reached consensus on their solutions, individual student volunteers presented their solutions to the class.   In spite of this group's inauspicious responses to my review question, when presented with using the concept in class, all students were successful and made an excellent transition into polynomials.