## Tuesday, 6 May 2014

### MFM2P - Days 54 & 55

Day 54

We started the class with another exercise in multiplying two binomials. I think the daily practice is helping them improve/solidify their understanding of how to do this. They miss doing Estimation 180 questions though...

Back to Barbie Bungee. Lots of good talk around how to find the distance bungeed when given the height and how to find the height given the number of elastics. Their equations were in terms of x and y so they needed to make the correct associations with their graphs. And do some algebra. There was also some unit conversion going on - most had taken their measurements in cm so they had to convert 4 m into cm to use their equation, but some groups had used inches when they collected data so they had a little more conversion work to do. Overall, it went well but it surprised me how long it took.

Day 55

Another exercise in multiplying two binomials. Most did it perfectly which meant that I could work with the few students who were still struggling.

Next, the Barbie Bungee challenge was on! I stuck with doing it in our classroom as there is really nowhere with a big drop at my school. I stood on a desk and showed them how I would be dropping the Barbies and told them to figure out the height. Thankfully, one student took that task on and wrote 2.94 m on the board (yay! they need to convert again). I gave them 5 minutes to figure out how many elastics they would need to and to get Barbie ready. It took closer to 10 (are slip knots really that difficult?!?) and then we began. The first Barbie jumped and hit her head hard. Boo! The second Barbie jumped and also hit her head hard. Oh no! Barbie #3 hit again! Barbie #4 looked like she would also hit, but her hair just brushed the floor and she was safe. Nice. Barbie #5 was safe by a long way. Barbie #6 wasn't quite ready so Barbie #1 got a second turn with 3 fewer elastics and had a perfectly safe and thrilling time. Barbie #6 was safe also, by a fair margin. It was a lot of fun and the winning group got lollipops. Sadly no pictures as I was the one dropping the Barbies.

We moved on to systems of equations. I gave them another jujubes and Smarties question to solve having taken out the pattern blocks and pennies. See here for more on this. Some students needed the manipulatives, others remembered how to do it without. They all had access to their comp books if they couldn't remember how to solve these types of questions. They all got the correct solution and we moved on to this (created by the awesome Sheri Walker):

(FYI - Tim Horton's is referred to as Timmy's here - they sell coffee and doughnuts, among other things. But it ain't no Starbucks!)

Here is what their solutions looked like:

Lots of reasoning without requiring any algebra since the number of donuts was the same for both days. Things will get a little more complicated tomorrow. I already had one student ask if there was a "better" way of doing these questions. Hopefully that will lead nicely into solving a system by elimination.