Wednesday, September 12, 2012

Categories of Number



During our first investigation in our unit Factors, Multiples, and Arrays, our class created posters of the arrays for various numbers. Using these posters, students put numbers into different categories based on the kind and number of arrays they could make. The class came up with five types of numbers - odd, even, prime, composite, and square. Numbers may fall into as many as three different categories. Here is a list of noticings for each category:


Odd Numbers:

* have a 1, 3, 5, 7, or 9 in the ones place

* have only odd factors

* odd x odd = odd


Even Numbers:

* have a 2, 4, 6, 8, or 0 in the ones place

* always have a factor of 2

* each factor pair must have at least one even factor

* odd x even = even, even x odd = even, and even x even = even


Prime Numbers:

* only have 2 factors (one and itself)

* only produce one array

* 2 is the only even prime number


Composite Numbers:

* have more than two factors

* make at least 2 different arrays

* can be even or odd


Square Numbers:

* make a square array

* have an odd number of factors

* follow a pattern of odd, even, odd, even, ...

* can be made by multiplying a number by itself (ex: 1 x 1 = 1, 2 x 2 =4, 3 x 3 = 9, therefore, 1, 4, and 9 are square numbers)


Students, can you identify a number between 100-200 that is composite and square? Leave a comment and share your answer (and y0ur reasoning)!!

4 comments:

  1. Thanks for posting them so I can study them!



    Pinchot 4th grade class

    Sofia D.

    ReplyDelete
  2. 10x10=100,11x11=121,12x12=144,13x13=169,14x14=196.100,121,144,169,196 are all composite and square numbers. for example in 12x12=144, 144 is a composite number becuase it has many factors and 12 is a square number.

    Markis

    ReplyDelete
  3. It is composite, because 50 and 50 25 25 25 and 25 thats four and there more than 2 but there is a bunch more!!!!!
    AUDREY:):):):):):)

    ReplyDelete
  4. 144 because 12x12=144
    Factors of 144: 1,2,3,4,6,8,9,12,16.18,24,36,48,72, and 144

    Sofia
    Pinchot/Barron

    ReplyDelete

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