This lesson plan uses arrays to explain division. If you don’t have the “Array A Day” worksheets, you can use regular graph paper to help you draw arrays.
Division Using Arrays
Context
Name: XXXXXXX Grade level: 3rd Group size: whole class
Date: March 10 Length: 20 minutes Sequence: introductory
Subject/topic: Division using arrays
Purpose
Standard/core: Standard 1, Objective 3a
Demonstrate the meaning of multiplication and division of whole numbers through the use of a variety of representations (e.g., equal-sized groups, arrays, area models, and equal jumps on a number line for multiplication, partitioning and sharing for division).
Learning goal: Students will know how to see a division problem in an array.
Major concepts: Arrays can be divided into groups of a certain size, or into a certain number of groups.
Assessment
Given a blank array worksheet, students will be able to divide the array into groups of a size and a number of groups.
Management
Self starter: N/A
Expectations: raise your hand to talk
Procedures: Watch the teacher and do what the teacher does on your own paper.
Fast finisher: draw more problems on the back of your worksheet
Instructional Strategies
Anticipatory set: “We have been building arrays with multiplication problems, but is there a way to divide an array?”
Tell objective: “We are going to learn what how to break up or divide an array into groups. Division is easier than you think!”
Instructions:
Input: “Let’s say we have a problem that looks like this… (write “18 divided by 3”)When we first look at a division problem, there are two parts we need to identify. The first number tells us the number of groups we have. There are 18 dots. So draw in 18 dots.”
Modeling: Write out the problem. Identify and label the parts. Draw in the dots (3 rows of 6 in each) on the array sheet.
Check for understanding: “Which one of these positions tells us how many we have? Show me with your fingers which spot has the total?”
Input: “The second spot tells us how we are going to group the dots. This says 3, so we want 3 groups. How can we make 3 equal groups?”
Modeling: Circle the dots so there are 3 groups of 6 dots each.
Check for understanding: “Show me with your fingers how many groups we have. How many dots are in each group?” Watch to make sure students have the correct numbers.
Input: “Now where do we write our answer? On the line. The answer is 6, so we write that on the line. Now what’s cool about this? Look at your picture and see if we can group them another way, maybe using the number 6. Look! We can also make 6 groups of 3 each!”
Modeling: draw circles around groups 3 each. There should be 6 total groups.
Check for understanding: “So, How many equal groups can we make with this problem? Show me with your fingers.”
Guided Practice: done as teacher does it on the overhead.
Independent practice: Have students do their own problem using a new worksheet (20 divided by 5)
Closure: “So now that we know what to do when we look at a division problem, we won’t be as scared, huh? We can use our array sheets to solve the problem.”
Resources
Array-a-day worksheet (2 copies per student)
Overhead worksheet, pens
Reflection
What went well?
What didn’t?
Improvements for next time?
Anyone else have good ideas for teaching division with arrays?
Squarehead Teachers 