Summary (scroll down for more details):
I asked some questions on Pear Deck to get students thinking about the parameters of the problem:
We discussed some of the above responses that did not meet the criteria of a total of 70 legs and why.
Students went to their boards in their small groups to solve this problem:
She has 26 animals all together.
There are 70 chicken & goat legs all together.
How many chickens? Goats?
Most groups were very unsure as to how to proceed in their solving. Most were simply guessing & checking various pairs of numbers. After a few minutes of allowing that productive struggle, when I noticed frustration setting in for some, I asked if anyone had considered drawing animal bodies & assigning legs to them? Here are the student boards:
We returned to our seats and our Pear Deck session & I put it into student-paced mode. I asked them to create the equations for the various parameters of the problem:
They struggled with this so I did some direct teaching about how to build the equation for this and the next slide:
Students were asked to use Desmos to graph their 2 equations & then sketch the graph and point of intersection:
Students were asked to develop an algebraic solution using the elimination method:
Not all of my students are comfortable with the algebra still (even though we’re at semester’s end now).
I like that we used 3 different methods of solving this problem; diagramming, graphing & algebraic. I want my 2P students to know they can always fall back on “less sophisticated” methods to solve these problems at evaluation time (as opposed to the algebraic solution).
The resources can be found here (including the Pear Deck interactive slideshow).
– Laura Wheeler (Teacher @ Ridgemont High School, OCDSB; Ottawa, ON)