Apps/Extensions Elementary

What’s my number? Number Sense performance task using QR Codes

Written by Lynn Scarbrough


Finished your number sense unit and want to check for understanding?  This QR Mystery Number lesson is engaging while showing proficiency.

My first grade students installed a QR reader/generator onto their Chromebook with step by step instructions.  I walked them through the Web Store and how to install the extension.  Then together we opened the QR generator and clicked on Edit this QR Code.  The last step was to click on the Free Text tab.

The instructions were to pick a two digit number.  100 charts were passed out with instructions to cross out numbers 1-9 and 100.  The children picked their “mystery number” and typed it into the QR code generator.  A two finger tap on the QR code pulls up the copy window.  They click on copy and open their document that was loaded onto Google Classroom.  The children were shown how to hold the control button (Ctrl) and then tap V to copy.  Once their QR code was on the page, they resized it to fit into the box.

Next the children create four different ways to describe their number without using the actual number.  It can be written in expanded form, with tens and ones, base ten blocks, given in an equation with no answer or a missing part, even or odd, ten more or ten less, given in a comparison (mystery #> given #, or given #< mystery #), a riddle (It is larger than 20 but smaller than 30), or other ways.  One way must be specific enough to figure out the mystery number.

When completed, the children print them out.  I collected the papers and put large numbers on the top.  I created a simple answer sheet with numbers and spaces.  The children then opened their QR code reader.  They took a paper, figured out the mystery number, and scanned it to see if they were correct, and wrote the answer on the answer sheet.  They continued changing papers until all answers were recorded.

The children were motivated and engaged throughout the lesson.  I did this with two different groups of first graders and both loved it.  You can have choices already on the doc or you can have it blank so they create their own.   It was interesting to listen to the children when the QR code did not match the clues on the page.  Every child wanted to finish even when they saw others were done.  It was a great way to see who understood number sense.



About the author

Lynn Scarbrough

Instructional Technology Coach, 1st Grade Teacher, @CaminoGrove @ArcadiaUnified