Grade 3: "Partitioning Sets"
(From: Mathology)
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This Mathology lesson plan can be accessed in both English and French by logging into your Mathology.ca/Mathologie.ca account and searching for Activity Card 17: Fractions: "Partitioning Sets"
Partitioning a set into equal parts and identifying the parts with fraction
Sorting a set using different attributes
B1. Number Sense: demonstrate an understanding of numbers and make connections to the way numbers are used in everyday life
• Fractions: B1.6 use drawings to represent, solve, and compare the results of fair‐share problems that involve sharing up to 20 items among 2, 3, 4, 5, 6, 8, and 10 sharers, including problems that result in whole numbers, mixed numbers, and fractional amounts
Explore set models of fractions
Develop and understanding that a set of objects can be considered as one whole
Partition sets
Use fractions to describe parts of a set
A set of objects can be considered as one whole.
When partitioning a set, the groups or parts do not have to be equal size.
We can use fractions to describe parts of a set.
Objects that can be sorted according to attributes, such as colour, shape, size (e.g., Pattern Blocks, stickers, buttons)
Math Mat 1: “Thinking Space”
Exit Ticket
Practice
(All Math Mats, Exit Tickets and Practice Pages can be accessed by logging into your Mathology account)
One-eighth / one-tenth / one-half / one-third / one-fourth / one-sixth
Numerator
Denominator
Attributes
Set
Fraction
Whole / Part
Equal parts
In this lesson, Pattern Blocks may be used to represent a set model of fractions. In a set model, we identify fractions within a collection of items, where the entire collection represents the whole (e.g., 1/2 of the class, 3/8 of the fruit).
When we look at fractions of a set, the parts do not have to be equally sized. For example, when we look at fractions within the class (e.g., What fraction of the class is wearing blue jeans?), the students don’t all have to be the same size. Likewise, when we look at a collection of Pattern Blocks and look at fractions related to colour within the set, we don’t need to worry about area. In this example, a set that contains 3 red trapezoids, 2 green triangles, and 1 yellow hexagon has a total of 6 items, and each block will represent 1/6 . It is helpful to explore set models of fractions with students because they encounter set models often, both inside and outside of school. Explicit learning about this model allows students to build a deeper understanding of fractions in general, including the ability to think flexibly across models. You may or may not choose to use Pattern Blocks, depending on what was observed in previous lessons (e.g., whether some conflation between set and area models surfaced with Pattern Blocks).
Students may benefit from prior experience with:
sharing items equally
partitioning shapes into equal parts
using ordinal number names
sorting sets of objects
Have 6 students stand. Use a fraction to label the group (e.g., six-sixths). Choose an attribute (e.g., hair colour) and have students rearrange themselves (e.g., 3 with black hair, 2 with brown hair, 1 with blond hair).
Use fractions to describe each part of the group (e.g., 3 of the 6 students, or three-sixths, have black hair).
Repeat with groups of 8 and 10 students.
Point out that when working with sets, the whole is the total number of objects in the set.
Give each pair a collection of 10 objects. Or project this set of 10 objects. Together, brainstorm a list of attributes that can be used to sort the objects (e.g., colour, shape, type).
Teacher Moves
Probing Questions:
How did you find what fraction that part represents? (e.g. area model or set model)
What attribute did you use to divide the objects into groups?
How many objects represent the whole?
How would the fractions change if you had one more _____ (e.g. yellow block)?
Encourage students to record their work on Math Mat 1: Thinking Space.
Are students able to use attributes to sort the objects?
Are students able to name a fractional part of a set?
Do students realize that the objects in a set can be different and that the parts do not have to be equal (e.g., can have different numbers of objects in each part)?
Do students understand that when partitioning a set, the set is the whole (e.g., when using 10 objects, the whole is 10)?
Have students share their strategies for partitioning sets.
Discuss how a fraction of a set still represents a fraction of a whole, only the whole is the whole collection (all the items) rather than the whole shape or line. When working with sets, items do not have to be equal sizes.
Show 12 buttons. Have volunteers arrange the buttons into equal groups in different ways. Use fractions to describe the equal groups.
For example,
There are 4 equal groups of 3. Each group is one-fourth of 12.
Count the groups: 1 one-fourth, 2 one-fourths, 3 one-fourths, 4 one-fourths.
Discuss what a numerator of 0 means for a set. For example, when there is a set of 2 red buttons and 4 blue buttons, we can say that zero-sixths of the set are green buttons.
To allow students to show what they have learned in this lesson, go to the Exit Ticket and/or Practice.
Highlight for Students
A set of objects can be considered as one whole.
When partitioning a set, the groups or parts do not have to be equal size.
We can use fractions to describe parts of a set.
How to Differentiate:
Accommodation: Provide a set of fewer objects all the same colour (e.g., buttons) and give students the attribute to sort by (e.g. number of holes, shape, or size).
Extension: Provide sets of objects that can be sorted in many different ways.
All assessments, in the moment feedback/prompts, and independent tasks can be accessed by logging into your Mathology/Mathologie account.
SEL Self-Assessments (English) and Teacher Rubric
Log in to your Mathology.ca / Mathologie.ca account to access Intervention and Extension activities, Professional Learning Videos and Assessment tools.
If you require support logging into your Mathology/Mathologie account, please contact Kerry Stack or Erica Doucet.
Use the Pearson Counters Tool (or Mathies set tool) to explore partitioning sets. Drag 2 stars, 3 apples, and 1 bear to the workspace. Find the fraction of the set each type of counter represents (e.g., 2 of the 6 counters, or two-sixths, are stars).
Then, drag 8 stars to the workspace. Find different ways to arrange the stars to make equal groups, then use a fraction to describe each group (e.g., 2 equal groups of 4; each group represents one-half of the stars).
Pearson Interactive Tools (log into your account) / Mathies app / Math Learning Centre)