Resource: Finding Factors of 20
Media Type:
QuickTime Video
Length: 2m 35s
Size: 7.7 MB
In this Cyberchase video segment, the CyberSquad is trying to figure out the location of Icky, the guardian of the Electric Eel of Aquari-Yum. The clue to his location lies in eight bubbles filled with pictures and numbers. The kids are told to find two numbers whose product is 20. Realizing that the pair of 10 and 2 is not an option, they use seashells to create an array to test out possible factors.
Alternate Media Available:
Transcript (Rich Text Format Document)
Loading reviews...Teachers' Domain, Finding Factors of 20, published October 30, 2009, retrieved on ,
http://www.teachersdomain.org/resource/wnet09.math.number.mul.wnetfactor20/
- Background Essay
- Questions for Discussion
- Standards
Print Background EssayDetermining a number's factors is a very important part of number theory. A factor of a number is a positive integer that divides evenly into the number. For example, the factors of 8 are 1, 2, 4, and 8. Factoring is an important tool used to divide whole numbers greater than 1 into two groups, prime and composite. A prime number has exactly two factors, 1 and itself. Composite numbers are whole numbers that have more than two factors. For example, the number 12 is composite because it has six factors, namely 1, 2, 3, 4, 6, and 12. Factors are useful in situations such as simplifying fractions or finding the greatest common factor or least common multiple of two numbers.
In order to represent factors visually, numbers can be modeled using rectangular arrays. For example, the number 18 can be shown as one row of 18, two rows of nine, or three rows of six. The composition of the array expresses the factors of a number. Consequently, these three arrays show that 1, 2, 3, 6, 9, and 18 are all factors of 18. When there are leftovers, neither the number of columns nor the number of rows is a factor. For example, if you try to express 18 using four rows, you find that you can put four in each row, but then there will be two left over, which is not enough to add one to each row. Therefore, 4 is not a factor of 18. Prime numbers can only be expressed as one unique array, which will look like one single row or column.
The factors of a number play a role in everyday life. For example, to determine the packaging and shipping options for a large number of items, manufacturers have to consider the arrangement of the items inside the package. If you look at a package containing six rolls of toilet paper, they are usually stacked three rolls wide and two rolls high. This shows that 2 and 3 are factors of 6. A package of 12 soda cans arranged as two rows of six is possible because both 2 and 6 are factors of 12. Now suppose you are arranging 24 photos, all of the same size and orientation, on a large cardboard presentation board. How can you arrange them so that you have an equal number of photos in each row? Knowing the factors of 24 can help you quickly consider your options: 1 row of 24, 2 rows of 12, 3 rows of 8, or 4 rows of 6.
To learn more about arrays, check out Harry the Substitute Teacher.
To find a lesson plan involving factors, check out Factors, Arrays and Commutativity.
We assign reference terms to each statement within a standards document and to each media resource, and correlations are based upon matches of these terms for a given grade band. If a particular standards document of interest to you is not displayed yet, it most likely has not yet been processed by ASN or by Teachers' Domain. We will be adding social studies and arts correlations over the coming year, and also will be increasing the specificity of alignment.Related Resources:
Source: Cyberchase: "The Icky Factor"
Resource Produced by:
Collection Developed by:
Collection Funded by:
