Complex Numbers and Speed Dating


About 3 years ago, I ran across this post from Kate Nowak called Speed Dating.  I have used it or a version many times.  Students do love it and often laugh about going home and telling their parents they speed dated in math class today!

She suggested placing desks so students are facing one another like this:


I used 2 colors of markers (one purple, one blue).  Each card contained one problem involving arithmetic, simplyfing complex number expressions, conjugates, graphing in complex plane and finding the modulus. I used the other color marker to create a parallel set of problems.   Each student in one row received a problem from the blue set and the other row from purples.  This enabled every student to experience at least one of each type probelm.


Students solved their problem, I confirmed or asked questions to clarify their work.  They became the expert of that problem.  Every person they “dated” would solve their problem.  As Kate’s post mentioned, you can easily assign problems to specific students to differentiate levels if needed.

Pairs would exchange cards, working the given problem.  The expert would check the other’s work, confirming or asking questions to help them correct any mistakes.  They would get their problem card back.  Front row rotates to next person.  Repeat.  By the end of the round, each student has practiced a variety of problems with immediate feedback as needed.

Exit slips revealed mistakes due to not paying attention to a given operation; a few need reminders of i^2 becoming -1 as one more step to simplify further; several still not comfortable with using conjugate to simplify rational expression of complex numbers.  Students enjoy working with others, an opportunity to be out of their seats.  Its a chance for them to ask questions of their peers in a smaller setting as opposed to whole-class.

Here is another idea…the Placemat Activity @cheesemonkeysf  incorporated to practice arithmetic with complex numbers.  Its amazing how quickly one forgets great little spins to use in the classroom.  Thank goodness for the open sharing of MTBoS to remind me!

4 responses »

  1. I am about to try this with quadratic expressions and graph matching. Thanks to you, it is going to become speed dating! (Valentine’s day, perfect match, etc.) the students will have to complete the missing information on their cards or interpret the graph, to find their perfect match. They will keep score on a card and then announce who they feel is their perfect match when the event is done.

    The card and the info they collect(solve) re their own equation or graph, along with the info from each partner will be the exit ticket. Every person will have one match and possibly two depending on the size of the class. (I use two sets of cards). Extra students are utilized as time keepers or roving experts to help stumped students, so the activity moves faster. The seating arrangement will help smooth out the process, because this event gets messy fast if every student is out of their seat trying to find the match.

  2. I just did this with my Alg 2 kids on radicals…and it was totally radical!
    They loved it. I loved it! They were helping each other and my one student who usually doesn’t even try to learn liked it. He fumbled around in the beginning on how to help his partner, but by the end of the period, he was confident. That was amazing to see.
    Thanks so much for your post! Will be using it often in class.

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