Math Journal Sundays - Comparing Perimeter and Area

12 May 2013
I'm going back a few weeks ago here, but I have a few perimeter and area ideas to share with you.

This first is a three-part math lesson we did for comparing perimeter and area.  We used a problem from the University of Waterloo's Problem of the Week - they have a great site full of problems that are perfect for three-part lessons.  You can subscribe to the site and get a new problem emailed to you each week, or you can browse through their collection and pick one that's perfect for your lessons.  Check it out HERE.  For this problem, students had to determine all possible dimensions for a 100 square meter area, and then decide which ones were the most sensible for a farm area.  We discussed our learning goal - comparing area and perimeter, and determining dimensions with a given area, and then students worked in pairs to find their answers.  For the sharing at the end, we did a gallery walk. I have this fantastic space outside my classroom with long rows of desks that is absolutely perfect for a gallery walk.  We displayed all of our work out there.  Each student was given 2 sticky notes (they could have more if they wanted) and they were to write a question or comment on the sticky note and place it on a paper.  I really like the thinking that goes on to these sticky notes - they really need to analyze the problem and solution to do this activity.

Following our gallery walk, we reassembled in the classroom to complete our Summary of Learning - a great reflection activity.  Students complete the three-part lesson with an independent task (very similar to the first problem) that they hand in for assessment.

I also have a Interactive Math Journal entry to share for area and perimeter.  This one compares the area and perimeter of rectangles (squares) and triangles.  We did a great hands-on activity before we completed the journal entry which really helped them master the concept.  I forgot to take pictures this time, but I did a similar activity last year, which you can read about HERE.

For this journal entry, we constructed a square and found the area and perimeter of the square (written on the inside).  We then folded it in half (they already knew this would halve the area) and found the area and perimeter of the triangle (which led them to the big idea that the area is half of the square, but the perimeter is not as the diagonal is a longer dimension).
For the proof I asked them to draw a different rectangle and triangle and solve for the area and perimeter of each.  For the reflection, I asked them to solve the problem in a different way (this is one of the reflection questions from my Math Reflection Fans).

That's it for today ... right now I'm enjoying a few quiet moments ... hubby took the girls to visit his mom for Mother's Day ... so I'm getting off the computer to enjoy the last of the quiet. ;)  Happy Sunday and Happy Mother's Day!


  1. Wow, this looks great! Thank you for sharing the website with the word problems, that will be really handy! And I love what you did with the square to the triangle! I love things that are visual like totally helps with understanding! Pinned it!

    Collaboration Cuties

  2. Thanks for sharing the site Jenn! It looks awesome - great opened ended question!

  3. I really like the triangle/square one. My kids always have SUCH a hard time remembering the formula for the area of a triangle (since parallelograms also get thrown in at the same time). Great visual you have there for them.

    Teaching in Room 6

  4. Jen~
    I used your fold-up surface area prisms and pyramids idea in my math notebook this year! My students LOVED it! You are so creative.
    If you are interested, here is the post.

    I mentioned getting the idea from you. Thank you! The angry birds idea is on the "To-Do" for next year!
    Coffee Cups and Lesson Plans

  5. So i have a question
    the math journals.. is that just for note taking and materials.
    then they use a math notebook for doing their work and other things.
    i am about to begin my first year teaching and i love your math journals idea but i am just confused on it