# Help! Why are my table sums incorrect?

In screens 8-13 of this activity, students should create a polygon, measure its angles and enter the angle measures in the table. The final row will then give the students the sum of the angles, rounded to the nearest angle. It was working correctly on all of the screens, until I added screen 14, which pulls all of the data from the activity into one table for students to copy into their note packet. Now, the tables on screen 8 multiples the total by 4, and then each following screen adds 1 to the total of the screen before it.

I tried deleting screen 14 to see if that would fix the problem, but it didnâ€™t. I donâ€™t think I changed anything else, so I canâ€™t figure out why the sums are wrong. Any help would be appreciated!

https://teacher.desmos.com/activitybuilder/custom/61f14fd201bd470a4a1c4542

Thanks!!!

After a little more experimentation, it seems like the sums work out correctly as long as at least 2 of the table inputs are decimals, but if there are 1 or no decimal values in the table, the sum is wrong. So, it seems like an issue with the way I did the rounding? Again, any help you can provide would be appreciated!!!

If you look in the CL under Table8, (and actually all tables after that point) after you sum all the values together there is an extra 0, which essentially multiplies the last value by 10. If you delete that zero it should work!

One thing I would recommend is to make sure students only use convex polygons in each of their drawings, as concave polygons will not yield the same results. Perhaps this is something you already planned to tell them in person, but I just wanted to add it in

Thank you!!! I had copied the CL from another activity and I guess I didnâ€™t quite get all of the edits correct.

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Did you mean the inverse of this? Are you referring to the need for the reflex angle value for concave polygons? If so, I donâ€™t know if you noticed or knew, but rather than clicking three points with the angle tool to measure each angle individually, you can click the interior of the polygon and all its angle measures will be labelled!

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Yup, thatâ€™s exactly what I meant Thanks for that catch!