Yesterday, I and several other teacher leaders from across the district, had PD and I learned something that shocked me.
Multiplication is NOT repeat addition.
Ok, I am no Master Mathematician. In Common Core language, I lack a mathematical mind. (I mean it, I have never had this.)
So I have always taught math trying to avoid teaching formulas or having only one method.
(Teaching the topic in multiple perspectives is an idea from my dad, did I mention he teaches Accounting at a university.)
Well, back on topic. The 5th grade teachers were talking about a new term they were going to be teaching the kids, scaling.
What is scaling you ask?
Well I Googled it, and this is what I found: Multiplication Ain't No Repeated Addition
The long and short of it. I sat there thinking "I HAVE SCREWED MY STUDENTS UP... FOREVER!"
Of course, I know that's not true.
Apparently, multiplying whole numbers this strategy works well. When it comes to multiplying fractions with other fractions, this does not work as a strategy.
As a third grade teacher, how have I fixed my mistake? I explained to my students that we are going to have repeated addition as a strategy, but when they get past 3rd grade, this strategy will NOT be an option, because the numbers will either be too large or too small for this to be a good use of our skills.
Please tell me I was not the only one who has taught it this way?