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All Things Second Grade Math!

Unit 10: Contextual Multiplication and Division

This unit bundles student expectations that address contextual multiplication and division situations and finding the area of rectangles using concrete models of square

units.


Prior to this unit, in Grade 1, students skip-counted by twos, fives, and tens to determine the total number of objects up to 120 in a set.


During this unit, students model, create, and describe contextual multiplication and division situations. Students use concrete and pictorial models to represent problem

situations where equal grouping is involved. Students use repeated addition or skip counting to determine the total number of objects and describe these situations using

language such as “3 equal groups of 5 is 15.” Students extend the understanding of equal grouping situations to include determining the area of a rectangle. Students use

concrete models of square units to cover a rectangle with no gaps or overlays, count the number of square units, and describe the measurement using a number and the

label “square units.” Students discover the relationship between a variety of equal group models and the arrangement of the objects in rows and columns to determine area.

Recognizing this relationship is foundational for students’ understanding of arrays and area models and future learning. Students also use concrete and pictorial models to

represent problem situations where a given amount is separated into equal-size groups and the number of groups is unknown (quotative or measurement division) as well as

where a given amount is shared equally among a known number of groups and the number of objects in each group is unknown (partitive division). Students describe these

situations using language such as “15 separated into 3 equal groups makes 5 in each group” or “15 separated into equal groups of 5 makes 3 groups.” Repeated exposure

to modeling and describing equal grouping situations leads students to the inverse relationship between repeated addition (multiplication) and repeated subtraction (division) that is similar to the inverse relationship between addition and subtraction.


After this unit, in Grade 3, students will transition to the representation of multiplication expressed using a multiplication symbol and a more formalized understanding

multiplication. The representation transition will begin with place value. Students will for the first time experience expanded notation, merging place value understandings and

multiplication representations. For example, students will transfer their understanding of 50 as 5 groups of 10 to 5 x 10. Later in Grade 3, students will begin to formalize

multiplication and division as they determine the total number of objects when equally-sized groups of objects are combined or arranged in arrays and determine the number

of objects in each group when a set of objects is partitioned or shared equally. Students will transition from repeated addition and repeated subtraction equations to the

multiplication and division symbols in equations. Students will use a variety of approaches to represent multiplication facts leading to the recall of multiplication and division

facts and the relationships that exists between them.

2.6A

This SE is asking students to do 3 different actions – model, create, and describe.


Model – use concrete objects and/or pictorial model to represent situation


Create – students write stories about equal groups


Describe – There are ______ equal groups. Each group has _______. So, there are _______ in all.


Introduction to Multiplication Lesson

Must be logged into your Wylie Google Apps Account

2.6B

This SE is asking students to do 3 different actions – model, create, and describe.


Model – use concrete objects and/or pictorial model to represent situation


Create – students write stories about dividing into equal groups


Describe – There are ______ counters. They are divided into _________ equal groups. Each group has _______ counters.


The Doorbell Rang
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2.9F

*Must use models that are squares (square sticky notes, color tiles, base ten flats, unit cubes). Students need to choose model based on efficiency.


*To determine area, count each unit individually, skip count, or use repeated addition.