Mystery Number Skype: Even a Six Year Old Can Do It

I’ve heard a lot about Mystery Skype calls over the past few years.  If you’re not familiar with this term, the basic idea is that two classrooms chat via Skype and try to guess where the other class is from by answering questions with only yes or no answers. I’ve always thought this would be lots of fun, but it has always seemed out of the reach of my six year olds, many of whom are still struggling to realize that they live in both a city AND a province.  Answering questions about our location would be out of the question.

I toyed with many ideas for ways that my class COULD do a Mystery Skype, (mystery letter, mystery word etc.) but it wasn’t until I saw a document about Mystery Number Skype that the lights suddenly came on.  For my class, numbers to one thousand (or even one hundred at that point) were out of the question, but suddenly, I realized we COULD do a call about numbers to twenty. You can get lots of ideas for doing a Mystery Number Skype with older students on the document I just mentioned, but if your students are still learning their numbers, this is…

How It Works in My Classroom

While there is no one way to do a Mystery Number Skype call, we’ve now done about a half dozen of them and this is how we have found it to work best.

  1. When we are getting ready to play mystery number Skype, everyone, including the teacher, writes the numbers up to 20 on a small whiteboard. (We got this idea from Karen Lirenman’s class during our first Mystery Number call.) Paper or a drawing app on an iPad could also work.
  2. Each class secretly chooses a number between 1 and 20. We usually do this before the call as well.
  3. Each class asks questions with yes or no answers to try to guess what the other class’s number is.
  4. For our purposes, we have one class guess until they get the correct answer and then the other class guesses. For my young students, this has so far worked the best.
Crossing Off Numbers

As the students determine which numbers have been eliminated, they cross them off or erase them from their boards. I do the same to help those who are still unsure of their numbers (or who were distracted and missed something). Besides being a great way to practice identifying the numbers, it keeps all of the students engaged during the call.

Hints to Get the Most Out of the Call

If you teach young students, remind them that it is a MYSTERY number, like a secret. In one of our calls this fall, a student in the other class kept bursting out “it’s sixteen!” I tried valiantly not to giggle as my students ignored this and went on guessing.

Agree on the rules ahead of time.  Assume nothing. In another of our calls, I assumed that the other teacher had seen a post about our first mystery number call on our classroom blog and was familiar with the way we had been doing this. Imagine the surprise of my students, some of whom were still working on their numbers to ten, when the other class’s first question was “what is two eights plus three?” (This could also have been a great way to practice numbers together, but was not what we were expecting!) You might also want to clarify what the other class knows about numbers. There is no use to ask if the number is divisible by 8 if the other class does not yet understand that concept.

Ready to Guess the Number

Think about who will ask the questions. At first, I allowed the more confident children to do this, but I now want to give a little nudge to quieter students who can also participate with some support.

I encourage what I call “fat” questions (these questions can eliminate multiple numbers) by discussing options ahead of time, but allow the students to ask questions of any kind.  My students’ questions range from “Is it eight?”  to “Does the number have a curved line?” to “Is it between sixteen and eighteen?”

Why I Love Mystery Number Calls

These calls work well on so many levels. I use Mystery Number Skype calls in our classroom because:

  • My students are writing the numbers to get ready. Purposeful practice.
  • Everyone is learning at their own level, whether that student is still learning to write the numbers, is struggling to distinguish between 11 and 12 (why do those pesky numbers not follow the ‘teen’ rule?) or is formulating questions that eliminate lots of possible numbers. We can all participate in the same activity, but the learning is differentiated.
  • While we are discussing numbers, my students are learning that other children far away are learning the same things as they are. This is a big step in global awareness.
  • My students are learning one more way to use technology to help them to reach their learning goals. This kind of digital literacy is important for children growing up in an online age.

If you have other great ideas for dong this that have worked for you, I’d love to hear them. We’re looking forward to more calls like this—soon we’ll be ready for numbers up to one hundred!

16 thoughts on “Mystery Number Skype: Even a Six Year Old Can Do It

  1. Hi Kathy,

    Have you ever played asynchronously, perhaps via a Google Doc or Twitter? I’d love to have one of my classes connect with yours, but I suspect we might have a time zone challenge! We’re in Milan, Italy.

    Thanks for the post! I’ve been encouraging my teachers to try this out and hope that your post I’ve just sent to them will be the motivation they need!

    Carrie Zimmer

  2. This is a great adaptation to Mystery Skype and especially useful for primary students. We have some excited kindergarten teachers at our school. Thank you for sharing how this works in your class, and providing hints for success. Initially how did you connect with other interested schools?

  3. Hi Kathy! We are doing our very first Mystery Number Skype this week. Thank you so much for explaining this type of skype call in such detail. I just emailed a link to this post to my co-teacher so that she can learn what this is and why we are doing it! We will certainly implement some of your great ideas.(I am also doing a tech in-service tomorrow and I would like to share this link with other teachers as well!)

    Also – just read about your experience with identity theft on Twitter. I am so sorry this happened to you. That is the type of thing that can cause us to run kicking and screaming away from social media. You have shown that it is so worthwhile for us to connect our kiddos through technology. I hope you will not make you lose all faith in your fellow Twitter users. We would certainly miss hearing your voice on Twitter.

    Thinking of you,


    1. It’s great to know that you found the post useful, Julie. I hope your Mystery Number Skype is as successful as it has been for us! And no, I won’t be leaving Twitter anytime soon. It’s made such a difference for me to be connected to so many great educators.

  4. We play a game in first grade and at the beginning of second grade that sounds as though it would be good practice before a Mystery Number Skype. We have a big numberline up on the wall. For first grade, I put a clip or magnet on 0 and one on 20. I pick a number mentally and write it on a piece of paper, but don’t let the children see. Their job is to guess my number. They use the same kind of questions you talked about and soon discover that “Is it greater than 10?” or ” does it have a 1 in the tens place?” helps them far more than “Is it 18?”. We tally the number of questions asked until they figure out the answer and they try to make the fewest possible guesses. For second grade we go from 0 to 50 or even 100. It sounds like playing this game might be good preparation for the higher “pressure” of doing it with another class. I have not tried Mystery Skype, but your post has definitely piqued my interest.

    1. This is a great game! In fact, I have done it a couple of times with my class when a planned Mystery Number Skype call was cancelled at the last minute for some reason. I have never tallied the number of questions, but that might be interesting to do. There is always the time that a student guesses wildly and actually gets the answer to keep some students thinking that might be the way to go. 🙂 My plan for next year is to actually do the number game with my class more often before we do it with another class, but I don’t think they feel any pressure. We Skype so often that they assume it is just part of life. I think they are surprised when they get to the next class and it doesn’t happen.

  5. Hi Kathy
    I loved reading your blog. I use Number Skype as often as I can when working long-term assignments. I find that children really love the collaboration with students and teachers in other cities and states and it brings life to the phrase “learning is fun”

  6. Hi, Kathy! Your description is exactly how I picture doing this with my K class. As we approach the 100th day, it would be so fun to connect with others to do number games! I’m looking for classrooms around the country and beyond who would be willing to play with us — we are in Wisconsin.

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