'15-'16 Sending Numbers

Hi Dawn

Would it be alright if I shared your binary sheet with the ECS teachers as well?


Sure. My kiddos have been using it. When we worked on Stage 10 Friday, they pulled it out of their binders and used it even though they did not have to. It helped clear up misconceptions.

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I used this lesson today and here were some of my basic points of feedback:

  • My students latched on to sending numbers pretty easily. Most of them opted for larger chunk sizes to avoid overflow. I think it would have been helpful force students into thinking of what the most efficient chunk size would have been for the three different squares. I think this would have pushed the conceptual understanding of binary a little more.
  • I think by giving students the decimal options, we gave them too much of a crutch. My students even self-elected to turn it off to challenge themselves.
  • I needed to do more of a share out at the end of the lesson to see how other people sent their messages.
  • I also think challenging students to create protocols that account for connected and non-connected points would have been a good extension.

The students enjoyed this lesson but I think it was a little too low on rigor for my students.

Thanks for this feedback Kaitie. We really hemmed and hawed about whether to include the decimal option in the simulator for the very reasons you cite. Good to know about the rigor level for you and you students. We’ll keep tabs.

When we tested the lesson we limited it to binary-only and some teachers reported it was too difficult/laborious to do all that binary conversion. I think it really depends how facile your students are with binary. We also thought it was potentially interesting to see how the decimal numbers respond when you change the chunk size for the bits, and that this might help students see/understand how the number of bits you choose affects the range of values you can express. I think if you want to reinforce binary stuff, it might just have to be a teacher-imposed rule at this point.

I think the “chunk” size was really helpful as well as to be able to see that in decimal and led nicely into the next lesson. I totally understand that the conversion would be tedious for some students and I could modify it to make our own restrictions. Thanks!

Cool. Also, if you’re looking for strategies for share-outs you might find this document helpful:
Teaching Strategies for the CS Classroom


So I need some help with the answer to the following:
Develop a protocol that allows the user to send a calendar date (mm/dd). What is the minimum number of bits necessary?
Answer: The minimum number is 9 bits.
Why not 6 bits?


You need 9 bits to be able to encode a month and day because it takes 4 bits to encode 12 months (4 bits can encode 0-15) and 5 bits to encode up to 31 days (5 bits can encode 0-31).

  • _ _ _ _ * _ _ _ _ _ *
    12 months 31 days

Does that help? Do you have a different way of getting to 6? If so we would be interested in hearing it.



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When I looked at the problem I was thinking about the month and day as a whole which I guess is the way that my students would also interpret it. I thought that the highest number is 31 and therefore 6 is the highest number of bits needed. The visual representation * _ _ _ _ * _ _ _ _ _ * helped. Thanks

Are there examples of protocols that students have generated? I can model the month/day protocol, but then I feel as if all my students will follow that example.

Hi Dillon,

We don’t have examples of what students have generated. Hopefully some other teachers can share. It might be good to give them the chance to try it out themselves before the demo. Hopefully then you can see where the students are headed on their own.

-CSP Team

I plan on letting my students start out with their Flippy Do…that will help them with the binary conversions and possibly save me some time. I am excited to try this lesson…it looks really neat.

Edit: I’ve finished the lesson. My kids, for the most part, are doing very will with binary conversions without the aid of their Flippy Do! Very happy about that!

Are there solutions to the Reflection Questions that are often on the Rubric Worksheets? If so, where can I find them? I have only been using these lessons for a few weeks and, while I really like them, I am still familiarizing myself with the structure of the course.

In case anyone missed this, here’s a link to how you can encode months and days. I found it very useful.

Hi Steve, reflection questions and teacher-only answers exist in Code Studio. If, while signed in as a teacher account, you don’t see the blue box below the reflection question (for example) here: https://studio.code.org/s/cspunit1/stage/14/puzzle/5

then you’ll need to request for validated teacher access, which you can do here by filling out this form.

On this lesson in particular (Sending Numbers) there are no solutions to the reflection questions because these reflection questions focus on instances of collaboration and problem solving, which will be unique to each student.

Hope that helps!


I had my students try to use the Internet Simulator in Lesson 8. They are not able to use it, there is not a Join Button. Is there a trick? (popup blockers? or something?) I am not sure what to do?

Hi Clair, sorry you’re having trouble with the Internet Simulator. Were your students able to successfully use the internet simulator in lesson 4?

One thing to double check is that your students are all in a section together – check out this forum post if you haven’t had a chance to do that yet: http://forum.code.org/t/setting-up-your-csp-section-in-code-studio/1670


I’m teaching this for the second time (block schedule) and it went so much better this time.

After I explained the basic concept of the exercise, I asked the kids to determine the dimension of each of the 3 grids (7 x 7), (15 x 15), and (31 x 31) and let them know that I’d be asking them to explain why those were chosen (the inference being that it wasn’t just happenstance). This is similar to the last question in the lesson.

I used the 7 x 7 grid as an example and worked through a bit of it with them, but obviously not giving them a specific protocol. Students were allowed to use their Flippy-Dos, but few needed them.

My evaluation is a Show Down: after they work out the protocol I separate them on opposite sides of the room. I let them know the dimension of the grid I want them to work on (they get that this will determine their optimal chunking), and I prescribe a minimum number of points that must be sent. Each student sends and receives. I collect both papers and see how the drawings match up. Fun!

A little follow up on this post: the results of the show down were most impressive. 6 out of 11 teams has identical diagrams (I matched up the front of the sender’s sheet with the back of the receiver’s sheet a and vice-versa.) The other groups, with one exception, had near matches. Next time I do this I will do it with some pre-drawn shapes of my own so kids can’t create too simple of a diagram. A good lesson!

Can someone explain the answer to what are the minimum number of bits for 96 * 96. I thought it would be 16 as you would need 8 for the x and 8 for the y. Why is it 14?

Hi Bryan,

Take a look at the binary place value chart below:

In order to make 96 - we see that we don’t need the 8th place value as that would be too high. So you only need 7 instead of 8 spots to make 96. 1 10 00 00 ( put spaces so its easier to see the number of zeroes).

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