Tuesday, March 06, 2007

I Am Amazed

Oh. My. Goodness.
Do you know what I witnessed today? I watched my daughter learn her +9 math facts in a matter of about....10 minutes. Now, you might think that I'm exaggerating here, but I am not at all.
Math-U-See teaches that 9 always wants to be 10, so he uses his vacuum hose (the round hole at the top of the 9!) to steal 1 from the number being added to him to make him 10. Therefore, 9+5 becomes 10+4, which is 14....well, that seems a little bit confusing as I write it, but it's less confusing when you're sitting there with the blocks in hand, saying it out loud and looking at the blocks. BUT, I looked at the blocks and said to Reilly, "Hey, here's an even easier way to think about it! You know you're going to make a teen number when you're adding to 9, right? (she nodded her head) Well, just look at the number you're adding, take away 1, and make it a teen!"
Just like that, she had it.
Have I said lately how much I love Math U See?


mamaduk said...


Now aren't you glad we convinced you to switch :-P


Lisa said...

*grin* Yes, I LOVE my JustMommies friends!! They're SUCH a good influence!

Sherri said...

Here's another interesting fact about 9's. When MULTIPLYING a by 9 you drop down one number less than the number you are multiplying 9 to...then add whatever you need to to it to equal 9. For instance...9 x 4. One less than 4 is 3 and
3 + 6 = 9. So the answer is 36.
Another one....9 x 5. One less than 5 is 4 and 4 + 5 = 9...so...the answer is 45. Isn't that great. It's easily done in the head, so they don't really have to memorize the 9's. Patrick has done very well with it.

Procrastamom said...

That is exactly how I have always added my nines! Cool, I had no idea it was actually a concept. And what Sherri said above about multiplying nines is neat too. I will have to tell my kids that one. Also, you can always tell if a number is divisible by nine if the numbers add up to nine or a multiple of nine. For example:

3654: 3+6+4+5=18
18 is a multiple of nine, so 3654 is divisible by nine. I learned this in high school and it has never been useful for anything until today. Whew, glad that education has finally come in handy!

I've been reading through your blog Lisa and really like it. I will put it in my reader, so I can see when you update.

Oh and I have a nephew named Declan, so we can be instant friends because we have soooo much in common! That and the t-shirt thingy! Yaaa! And many more exclamation marks, just for good measure!!!!!!!!