## Friday, November 8, 2013

### Lesson 6 - Year 2

Introduce the concept of x as an unknown
3 + ? = 5 How do we call ? in math? How can we solve this?
What about ? – 2 =4

The kids can easily solve these, but they can’t explain how they do it “We have done a lot of these in school already so we know the answers” Me: “But what if I gave you one that you haven’t already solved, then how would you solve it?” Kids: “We know how to do all of them (equations) already so you won’t be able to give us one that we don’t know!” Hmm… Anyway, since they can’t explain, life examples are always good. They have to learn that if the equation starts “balanced (equal on both sides)” then if they do the same operation to both sides then the balance will stay (because they didn’t think so at first).

Show with a problem:
*pretending that all apples weigh the same, all bananas weigh the same, all oranges weigh the same
“If you had a scale with an apple and an orange on each side, and it was balanced, then if I take an orange off of each side, will it still be balanced?” Kids: “NO! Of course not!” Well, we’ll need to work on that…

2 apples and 1 orange on one side of a scale, 3 oranges on the other side in this example, are 2 apples equal to 2 oranges? How do you know?
Play with a balance scale and small cubes – taking the same amount away from both sides
Come back to the problem and try it again with new understanding and do a couple more of the same type
By the end of this part of the lesson, the kids should understand that if you take the same amount (of the same thing) away (or add the same amount) to/from each side of an equation, it will stay equal. If the kids still don’t understand, have them do a few more equation examples of the same type, and let them experiment with adding/subtraction amounts from each side and checking if it still stays equal. That should most likely be enough for them to understand.

Try a few substitution problems:
What is apple + apple + apple if apple = 2?
What is orange + apple + banana if orange = 2, apple = 3, and banana = 4
With those same numbers, what is 2 apple + 3 orange?
This is pretty easy and not too interesting but it is good practice and will be useful later on when it gets a lot more complex.

Show the kids a “magic trick” and have the kids figure it out and then do it themselves (every person should get a turn)
Take 10 cards- lay them down slowly one after another until your partner says stop. When they say stop, show them the card that you were going to put down next but haven’t put down yet  (and DON’T LOOK AT IT YOURSELF), and then put that card on top of all of those cards that you have already laid down. Then, put that stack of cards under the rest of the 10 cards (whatever’s left). Find your partner’s card.
I used cards that had pictures on them
The kids thought that it was amazing and said that they will show it to all their friends J The trick is really just that you count how many cards you put down before your partner said stop, and then you subtract that number from ten, and the number of cards that you go through from the top of the deck will be that number. Example: Let’s say you put down 3 cards and then your partner said stop. You know that you are showing them the fourth card. 10-4=6, so after putting the cards you have already put down+your partners card under the rest of the pile, you count 6 cards from the top, and that card will be your partner’s. It actually involves more math than it seems like, and for a kindergarten-age child, is pretty complicated. Anyways, it’s an activity that the kids are enthusiastic to do, and that in itself is already very goodJ.

Handcuff puzzle- escape!
I made the handcuffs out of rubber bands tied together with yarn.
They LOVED it! They were completely tangled up with their partner, stepping under and over the string (and of course giggling). After a couple of minutes, the parents got involved, wanting to try it themselves, and trying to help their kids (and not succeeding). J I asked if they wanted me to show them the solution, and the parents said that “no”, they would need to think about it for another week until next class, and then, after they get to play around with it, then I can show them the answerJ. It was a complete mess. This is really an awesome activity.