I was surprised to find that class was cancelled today when I checked blackboard. It is that time of year for the nasty flu to be floating around! Feel better soon, Maria.
I have been exploring star polygons, which are in the activity approach book beginning on page 111. It took me a couple of tries to get the pattern down, but they are fun once you figure them out. It reminds me of the Spirograph toy. My son actually has one right now and we haven't even opened it yet! I checked on you tube for demonstrations of the star polygon, and I found this very cool presentation:
I downloaded inkscape and tried the same demo. I still have some work to do. I can't get the polygon to stay closed, so when I start drawing the lines they continue outside of the points. If anyone else decides to give it a try, let me know how it works out for you! I will try again later!
Monday, October 12, 2009
Wednesday, October 7, 2009
Check out this method for divisibility by seven!
The divisibility by seven rule that Maria gave us today seems easy compared to this rule: I didn't try it yet, just reading it gives me a headache! Go to this link:
http://www.maa.org/mathland/mathtrek_05_23_05.html
For those of you who didn't take notes on this but are curious how it works, here is by 11.
Divisibility by 11:
Divisibility by 11 is the most interesting of the above tests (7 will be studied below). We do two sums (the odd numbered digits and the even numbered digits), subtract one sum from the other, and see if this is divisible by 11. By the way, if we end up with zero, then that is divisible by 11. We can repeat that process, just as we did with 3. Let's look at an example:
348719033+8+1+0=124+7+9+3=2323-12=11Is divisible by 11
We can, of course, do the summing in different orders. In fact we can just go from left to right adding and subtracting alternate digits: 3-4+8-7+1-9+0-3=-11 (divisible by 11).
Make sure you study the divisibility rules! They will be on the next test!
http://www.maa.org/mathland/mathtrek_05_23_05.html
For those of you who didn't take notes on this but are curious how it works, here is by 11.
Divisibility by 11:
Divisibility by 11 is the most interesting of the above tests (7 will be studied below). We do two sums (the odd numbered digits and the even numbered digits), subtract one sum from the other, and see if this is divisible by 11. By the way, if we end up with zero, then that is divisible by 11. We can repeat that process, just as we did with 3. Let's look at an example:
348719033+8+1+0=124+7+9+3=2323-12=11Is divisible by 11
We can, of course, do the summing in different orders. In fact we can just go from left to right adding and subtracting alternate digits: 3-4+8-7+1-9+0-3=-11 (divisible by 11).
Make sure you study the divisibility rules! They will be on the next test!
Prime numbers
As always, today's class was insightful and very helpful. The method that Maria gave us, the sieve of Eratosthenes' was the easiest method I have ever used to identify prime numbers.
Just to review, a prime is a natural number that posesses exactly two different factors, itself and 1. For example, 17 is a prime number because it has exactly two different factors, 17 and 1. 15 is not a prime number, because 15 has more than two factors; 1 and 15, and 3 and 5.
I liked using the blocks today to demonstrate the rectangular array of division. I am a very hands on learner, so manipulating the blocks makes a lot more sense to me than just looking at pictures in a book. I am planning on teaching early elementary, so when I look for links on the web, I tend to look for kid friendlysites. Check out this site for an easy to read chart on prime numbers, as well as many different educational aids for all areas of study!
http://www.factmonster.com/math/numbers/prime.html
Have a great evening!
Just to review, a prime is a natural number that posesses exactly two different factors, itself and 1. For example, 17 is a prime number because it has exactly two different factors, 17 and 1. 15 is not a prime number, because 15 has more than two factors; 1 and 15, and 3 and 5.
I liked using the blocks today to demonstrate the rectangular array of division. I am a very hands on learner, so manipulating the blocks makes a lot more sense to me than just looking at pictures in a book. I am planning on teaching early elementary, so when I look for links on the web, I tend to look for kid friendlysites. Check out this site for an easy to read chart on prime numbers, as well as many different educational aids for all areas of study!
http://www.factmonster.com/math/numbers/prime.html
Have a great evening!
Sunday, October 4, 2009
Tips for base 5 counting
The introduction of other base systems really makes me appreciate base ten. It certainly takes practice to understand. Using games is a great way to teach new concepts, at any age, as we have found in class. I spend time volunteering in my son's kindergarten class, and the teacher is always using games to teach. It's great because the kids pick up on things quickly and they are not stressed and pressed.
Class on Wednesday was actually a lot of fun. With the continuous cuts that our education system keeps enduring, teachers are given more and more responsibilities with their classes. Many schools are losing extra classes, like physical education, art, music, etc. " Math in Motion" is a way to incorporate physical activity with learning math. I can certainly imagine a group of students, 3rd grade on up, lined up at the whiteboards and competing with addition, subtraction, etc.
When you are reading through section 3.2, check out Math Activity 3.2 on page 142. This would be a great game to play with older elementary kids when they are learning the base 5 system. A little competition is great, and a memorable experience when you are learning something new.
For tips on base five, check out this link:
http://mathforum.org/dr.math/faq/faq.bases.html
I found it to be very helpful!
Class on Wednesday was actually a lot of fun. With the continuous cuts that our education system keeps enduring, teachers are given more and more responsibilities with their classes. Many schools are losing extra classes, like physical education, art, music, etc. " Math in Motion" is a way to incorporate physical activity with learning math. I can certainly imagine a group of students, 3rd grade on up, lined up at the whiteboards and competing with addition, subtraction, etc.
When you are reading through section 3.2, check out Math Activity 3.2 on page 142. This would be a great game to play with older elementary kids when they are learning the base 5 system. A little competition is great, and a memorable experience when you are learning something new.
For tips on base five, check out this link:
http://mathforum.org/dr.math/faq/faq.bases.html
I found it to be very helpful!
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