Wednesday, October 31, 2012
Article #2
This is one of my most favorite articles from NCTM about subitizing and structuring number. There has never been an emphasis on structuring number. What is subitizing? What is the difference between perceptual subitizing and conceptual subitizing? What are some key points you will use in your math instruction?
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ReplyDeleteSubitizing is "instantly seeing how many." It is the core word behind the word "structure".
ReplyDeletePerceptual subitizing is recognizing a number without using other mathematical processes. It makes single "things" to count. Conceptual subitizing is an advanced organizing technique that people "just know". They see the number patter as a composite of parts and as a whole.
I will use the key points on page 402 and 403. Some guidelines in particular that I will follow is to not subitize groups in pictorial context and regular arrangements (symmetrical, linear, rectangular).
I remember reading this article when I took the first AVMR class with Christina Miller. It makes so much more sense now! I'm glad I had to reread it. :)
What is subitizing?
ReplyDelete"The direct perceptual apprehension of the numerosity of a group." In other words, students can instantly see how many are in a group while recognizing that group is made of parts. I appreciated what Freeman suggested this meant, the person can see the group - the whole - and each unit at the same time.
What is the difference between perceptual subitizing and conceptual subitizing?
When a student is able to conceptually subitize, he or she is able to view number and number patterns as units of units. They can partition dots, yet know what the whole is. A student who perceptually subitizes can tell you there are 3 dots, yet still sees the dots as separate units that he or she may need to count.
What are some key points you will use in your math instruction?
The article first made me think about the types of units I use. I have seen pictures used instead of dots on cards. I suppose one would want to make sure the complexity of the drawings does not hinder the actual goal of subitizing.
I have used many of the suggested activities (especially quick images), but I look forward to trying them all. I especially will use the auditory activities with my kindergarten and first grade groups.
The estimation activity seemed extremely valuable.
The importance of subtizing in the development of student’s number sense was really highlighted and gave me a better appreciation of its importance!