Discussion Question: What is wrong with the following statement?
5−7=2

John: I don't know.

This answer will not get John any credit because it doesn't contain any specific math information! Its ok for John to say that he doesn't know, but he needs to give more details if he wants to get any credit for this!

Jessica: This looks right to me, because 5 and 7 are 2 units apart.

Jessica's answer is incorrect, but she has given us specific math details that explain why she thinks that 2 is the answer. She will get partial credit for this answer.

Maria: The answer is −2.

This answer is correct, but it is not going to get Maria credit because she didn't really answer the question! The discussion question asked for them to explain what is wrong with the statement, but Maria hasn't done this! When you are asked to explain what is wrong with a given answer, you cannot just give a different answer from the given one, because many problems have more than one right answer - so offering an alternative answer does not prove that the given answer is wrong (maybe both answers are right)!

To get credit for this, Maria needs to come back and explain in detail why the answer cannot be 2. Then she can explain why it should be −2 instead.

Pia: The problem with this statement is that, while 5 and 7 may be 2 units apart, it forgets to take into account that 7 is bigger than 5. So when we take 7 away from 5, we get −2 instead of 2.

This is a really great answer! It is correct, and Pia gives us some really clear, specific details about what is wrong with the given statement. She will get full credit for this! (But remember, to get all the credit for the discussion board this week, Pia still has to respond to two other students' questions and to any comments I or other students make to this post!)

Moses: That's a really good answer, Pia. It really helped me understand the concepts.

It is great for Moses to let Pia know this, but he can only post this to the discussion board if he realizes that he won't get any credit for it! If he just wants to tell Pia that she helped him, then that's great. But if he wants this post to count towards the two responses he is supposed to make to other students, then he is going to be disappointed! Because this post contains no specific math details, it isn't worth any credit!

Yi: Pia, your explanation really helped me to understand the concept better. Before I read your post, when I was calculating 5−7, in my head I was actually doing 7−5. After I read your comments, I realized what my mistake was: because we are starting with only 5, when we take 7 away from that we take away the 5 that we have and then 2 more that we don't have. So what we have left when we take 7 away from 5 is 2 less than nothing, which is −2.

Yi has also told Pia how she helped here, but she has been very specific about what happened with the math in her mind once she finally understood. Because she has given so much clear specific detail, this is an excellent answer. Yi gets full credit for this! (But remember, to get all the credit for the discussion board this week, Yi still has to write her own post and to respond to one other student's post!)

FOR EVERY DISCUSSION BOARD QUESTION, this is what is required to get full credit on the Discussion Board:

• Post your first response to the discussion board by the FIRST discussion board deadline (see the deadline given in the Discussion board column of the Assignments page for this week).

• READ ALL OTHER STUDENT POSTS before the final deadline, and use what you learn from this to correct your own posts. If you find that another student's post makes you reconsider your answer, then you should go back and correct your post, even if that student has not commented specifically on your work.

If I find that you have not been reading other student posts, you will lose points. (If your answer has obvious errors that have been addressed by other student posts and you never repost to correct these, then it will be clear to me that you have not read the other students' posts).

• Respond to all student and professor questions and comments on your work.

If I respond to your post and ask you to fix or clarify something you’ve said, you must respond to my post.

If other students give you feedback on how to fix your answer or explain why they think that your answer has an error, then you must respond to them by either correcting the error and reposting your answer, or if you think they are mistaken and that your answer does not have the error they have described, then explain clearly to them why the error they have pointed out is, in fact, not an error.

If you receive important comments from me or another student just before the deadline, you may respond to them after the deadline until the discussion board has been graded (which is usually about one week after the discussion board deadline has passed), if you have submitting all your other discussion board posts by the deadline. This is the only instance in which you can post to the discussion board after the deadline has passed. without prior permission from me.

• Reply to AT LEAST TWO of the other students’ posts for each question by the final deadline for that week (see the deadline listed in the Deadline column on the Assignments page for that week).

Your replies to other students’ posts should say something useful! It is fine to reply to another student, “Your answer really helped me to understand the concept better!”, but this post does not contain any information about the math itself, and therefore will not count as one of your two responses.

Grading Rubric for Discussion Boards: Each discussion board is worth 10 points total:

• 4 points total can be earned for reading all other student posts and for submitting an answer to the question that is initally on time (for the deadline for initial submission) and which is complete, correct, and clearly explained with sufficient detail. (The correctness of your post will be judged by your final submission, so that if you correct an initial post, the initial errors will not count against you.)
• 2 points for each required response to other students' posts, for 4 points total. Full credit can only be earned for posts that are submitted on time and which contain significant mathematical content.
• 2 points for your responses to other students' questions made in reply to your post - again, these should also contain significant mathematical content.