1510 Prime Time Numbers

When it comes to prime numbers I ask myself, who comes up with these numbers? At first look, they are just numbers, but what really makes them prime numbers? By definition, a prime number is one that can only be divided by one, and itself, everything else is a composite number. How did mathematicians figure this out? Is there a pattern?

Come to find out, there is a pattern! A Greek man named Eratasthenes, studied mathematics over 2000 years ago came up with a model that is called the Sieve of Eratosthenes. Essentially, it takes the first prime number, 2, and then crossed off every 2nd number from there on out. The next prime number is 3 so, he crossed out every 3rd number and continued that pattern with each prime number. All the numbers he was crossing out were composite numbers. He was making a sieve that drains out composite numbers and leaves prime numbers behind. Is this not crazy? I'm just amazed on how this works.

The question you always hear from a student in class is, why are prime numbers important? Is there any use for them outside of math? You bet there is a use for them and I bet you didn't even know it. Large prime numbers are used in RSA cryptographs for sending secret information like your credit card over the internet. The first step is to take 2  large prime numbers, multiply them together and their product is what is what makes factoring out the prime number difficult. Watch the video and try and follow along, it's pretty complicated after the first step I just explained but well worth the view.

1510 Week 2 post - Base 10

The bases are loaded and with this weeks reading about 3rd graders learning about pace value, we as teachers are striking out with our at-bat in teaching them this material. Place value, as simple as it sounds, is very confusing to students because they don't understand the value of numbers more than 0-9.  I can see how this is confusing to a student, you are taught at a young age all about your 10 fingers and there isn't much emphasis put on what you do after that. The number 10 is held in high regards and is like this magic number that we never go above. So, with a number like l5, students don't recognize the place value and that there is a tens and ones position. A number as simple as 15 is looked at as a 1 and a 5, not as 10 and 5.
The one thing our Hindu-Arabic number system has going for itself is that is is very quick to use, especially when you want to write out a number. It's just not as easy to understand for new learners. Looking at the Mayan and Egyptian numbering systems, they use symbols to illustrate their numbers. This proves to be very easy for learners to assign symbols with the place value because they aren't all the same like with the Hindu-Arabic, 0-9 numbering system.
Pictures are always more fun to draw than numbers, but with the Egyptian and Mayan number system, you have to draw a lot of pictures or symbols to compose a number like 528. As great of an artist that I think I am, I would still try and short had some of the symbols when trying to solving a math problem in one of these systems. These systems look to be great for learning, but not practical in their use in everyday society.