Lesson: Properties lesson 5

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Lesson Objective

What is an array?

Lesson Plan

Edward Brooke Charter School

I.                   Curriculum Standards

ü Count by 3 to 30 and 4 to 40, starting at any multiple of 3 or 4.   [M.1.2.a]

ü Define multiplication as repeated addition. [M.11.2.a]

ü Explain the connection between multiplication and skip counting. [M.11.2.b]

ü Create arrays as models of repeated addition.  [M.11.2.c]

II.                    The Point

What is an array?

III.                Materials Needed

Copies of 2.10.5 Practice Problems

Copies of 2.10.5 Math Workout

Counters

Slates – optional for practice

IV.                 Lesson Outline

Time:  60 Minutes

30 min. – Arrays as Repeated Addition

15 min. – Math Workout

10 min. -  Mental Math

5 min. -  Summary

V.             Learning Activities

1.   Arrays as Repeated Addition (30 min.)

In this lesson, students work to solidify their understanding of arrays as models of repeated addition.

Review the big ideas from Lesson 2.10.5 with students.

Students practice finding the total number of items arranged in arrays groups using counters and sketches.   Students use repeated addition/ skip counting to find the total number of objects.  They represent the repeated addition with multiplication number sentences on paper or slates.

Students practice:

• describing arrays
• drawing arrays
• finding the total number of items in an array

a.    Describing arrays

Create an array on the board or the overhead:

b.    Drawing Arrays

Draw an array that has:

4 rows

5 counters in each row

How many dots in all?

Write the multiplication number sentence.

Draw an array that has 8 dots. (multiple possibilities)

How many rows?

How many dots in each row?

How many dots in all?

Write the multiplication number sentence.

c.   Distribute 2.10.5 Practice Problems (4 pgs) to students.

On the board or overhead, show students how an array can also be created by shading squares on grid paper.

Instead of drawing a dot for each item in a row, you shade a square to represent the item.

The egg carton in item #1 would be represented by shading 2 rows of 6 squares.

Complete the first 1-2 pages of this practice packet together.

We are moving students to showing arrays on grid paper to facilitate the transition to the area model for multiplication/division in third grade.  Students will use the area model in the future for whole number multiplication/division as well as multiplication/division of fractions.

Students complete the 2.10.5 Practice Problems (2 page problem set) as guided, supported, and/or independent practice.

2.  Math Workout (15 min.)

Students complete 2.10.5 Math Workout.

3.  Mental Math (10 min.)

Students participate in a Mental Math practice session.

4.    Summary (5 min.)

What is an array?

Lesson Resources

 2.10.5.WO (Full).doc 64 2.10.5 Practice Problems.doc 54 2.10.5.doc 23