## Thursday, 20 October 2016

### Algebra for 8 year olds

This afternoon we had a staff meeting with Sue Pine, our maths PD lady.

After having a great observation and getting lots of testing done throughout the day, I was ready and eager to learn from her.

Now if you are anything like me, when somebody says 'algebra', you think of this...
This is exactly what I thought of - ala year 12 Calculus..

So, how the heck does this happen for my 8 year olds?

We started with this blue piece of paper. The questions at the bottom are
-how much does a T-shirt cost?
-how much is a drink?

Sue told us NOT to use algebraic equations to solve, so I used trial and error which made the most sense to me.

I first started with a t-shirt being worth \$20, hence a drink being worth \$2, based on the first equation. The second equation then didn't add up to \$30.. so it couldn't be that..

So, I made the cost of the drink higher. I tried \$17 for a shirt and \$5 for a drink.. again, it didn't add up for the second equation. This time it was too much..

So I made the cost of the drink less.. this time \$3 and the t shirt was \$19.

Again, not enough for the second equation. So I made it in between - \$4. and hence t-shirts cost \$18.

Booyah!

Another way we could have solved it was by using what was the same in each equation - each one had one t shirt and one drink. Half of \$44 is \$22, so one shirt and one drink cost \$22 together. In the second equation, you are left with \$8 so each drink here costs \$4.

Then we talked about the maths progressions and put them in order..

I see stuff like this all the time, especially on my Facebook feed where people fight over the answer. I now realise, this is algebra! This isn't just some silly game.
Have a go yourself!

I found this meeting with Sue very useful, as it broke down what algebra actually looks like for different aged children. It's not all about equations, (well not for the age of my students anyway..)
Thanks Sue!