Kindergarten, Learning, number sense

Subitizing- More than Just Dots

Subitizing

Subitizing is the ability to quickly identify the number of items in a small set without counting.  To do this effectively students are required to “see” collections or groups as opposed to counting one at a time.  They need to see a configuration of objects and instantly know how many is there.  This skill requires practice and support.  The practice can come from things such as dot cards, ten frame cards etc.  In these cases students can be shown the card quickly and then asked the question “How many did you see?”  The support comes from the conversations that ensue.  As students are asked to articulate their thinking about what they saw and how it supported them in knowing “how many” their thinking grows.  As students hear from others how they “saw” the collection their thinking is supported.  

The value of subitizing with your students is considerable.  Research indicates that subitizing can play an important role in the development of mathematics skills including addition/subtraction, and multiplication/division.  It can also support students development in number sense and can serve as an indicator for student success in mathematics. 

Our curriculum has specific subitizing outcomes for Kindergarten and Grade 1 students.  However, the value of this work can extend well beyond the primary grades.  Subitizing activities can serve as a powerful warm up or Minds On activity to start a mathematics class at any level. 

To support you with subitizing with your young mathematicians check out these Subitizing Cards.   

Base Ten Blocks       Counting Fingers           Dot Cards          Tally Marks       Ten Frames

Computational Fluency, Learning, Math, number sense

Student Inquiry into Computation with Cuisenaire Rods

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At our last math community meeting teachers were given an opportunity to explore the provocation shown above.  This provocation was provided to support wonder, curiosity, creativity and multiple opportunities for computation.  Teachers were able to create designs with addition, and multiplication using one of my favorite computation manipulatives…Cuisenaire rods.

I chose this activity and these manipulatives for many reasons.

  • It allows students to explore part-part-whole thinking
  • It provides opportunities for multiple computations in an engaging way
  • It brings creativity, and design into mathematics
  • It allows for collaboration, and conversation
  • Students can discover relationship, and multiple interpretations

After our professional exploration many teachers took this activity back to their classrooms and shared it with their young mathematicians.  Below are some examples of what the students came up with in classrooms.

As a follow up students can bridge the concrete to abstract continuum by recording their computations/designs pictorially and abstractly on a sheet.  Initially, recording sheets could have pictures of coloured rods to match the concrete representations the students created.  As students progress in their level of abstraction they can switch to just marking the value on the rod.  Abstractly, they would record the equation their design represents.

Below are some supports that can help you incorporate Cuisenaire rods into your classroom.

Student Desk Cards

Whole Numbers

Decimal Numbers

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Build It! Draw It! Write It! Student Recording Sheet

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