The same subject I didn't touch until 7th grade, the subject that made me want to pull my hair out, the subject that insisted that I turn a letter into a number... that subject is what we tackled, and conquered, in class yesterday.
In particular, we tackled the Associative Property of Addition.
It all started with the Doubles +1 addition math strategy.
*Remember- a Doubles fact is two numbers, that are the same, added together. For example 1+1, or 5+5.*
To introduce the lesson, students had to find the closest doubles fact that would get close to 15 without going over. First we looked at the number chart.
So, was that about as clear as mud? Yep, it was for us too.
The good news is that the Doubles +1 strategy is just a strategy for showing students that numbers can be broken into smaller numbers.
So, instead of this introduction, I introduced the lesson this way:
Me: I don't like big numbers. They are mean and look at me funny. I'm going to break apart some big numbers, that way I'll never have to look at them again!
Student: How can numbers look at you mean?
Me: They make things hard and make my brain hurt. I can't handle it, so I've got to chop them down to size! (evil laughter)
Me: How do you know?
Student: Because it equals 14 and 14 is smaller than 15.
Me: Do you know what you just did?
Student: Um... no?
Me: You just did... Algebra!
Me: You're saying it wrong. It's not algebra, it's.... Algebra. Say it like it's magic, and with the hand motions.
Student (placating Mrs. Delk): What is Algebra?
Me: It's an insanely difficult form of math that I didn't touch until 7th grade.
Student: But I did it and I'm not in 7th grade.
(Class nods in agreement)
Me: That's why I'm so excited! My class is so advanced!
Me: Before we go on, I have to introduce you to a mathematical invention called Parenthesis.
Different student: What's parenthesis?
Me: It's when you lock numbers up and they can't come out until they learn how to work together!
Me: Whatever numbers are in parenthesis, those numbers have to do their job first. Check this out.
Me: It's called the Associative Property because the numbers have to work like associates, they work together! So, we lock the doubles fact together, solve, then we take the answer and add it to the other number outside of the parenthesis! TA-DA!
Student: That's algebra?
Me: No dear, that's... Algebra! (with proper hand motions and inflection)
Me: And, check this out!
Me: It works with the other numbers too! You can lock the other numbers in parenthesis, solve, them add the answer to the remaining number, and you STILL get the same answer! It's number magic!Students cheer in glee!
Student: Mrs. Delk, my brother is in Algebra class in school. He does this all the time!
Me: This means you can help him with his homework!
We practiced a few more times and it was a hoot. We practiced splitting big numbers into smaller numbers and we tested our Associative Property of Addition.
*Basically, when dealing with addition, it doesn't matter the order in which you add the numbers, it will come out the same answer.*
So, how to we break apart numbers? By doing a little thing called Factoring. We break apart numbers by finding the different factors (numbers) that make the whole number.
Here are 2 of my soldiers finding the Factors of the number 13. They were promised Cub Cash if they could keep factoring numbers until they reached the lowest number they could go.
Hooray! Now we know we never have to deal with mean big numbers ever again!