Grade 3 · Mathematics

Determine the total number of objects when equally-sized groups of objects are combined or arranged in arrays up to 10 by 10

Quarter 2 · Week 6 · TEKS

Standards Alignment

  • TEKS.MATH.3.04D primary
    determine the total number of objects when equally-sized groups of objects are combined or arranged in arrays up to 10 by 10;
  • TEKS.MATH.3.04E primary
    represent multiplication facts by using a variety of approaches such as repeated addition, equal-sized groups, arrays, area models, equal jumps on a number line, and skip counting;
  • TEKS.MATH.3.04F primary
    recall facts to multiply up to 10 by 10 with automaticity and recall the corresponding division facts;

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Lesson Overview

This Grade 3 mathematics lesson focuses on helping students determine the total number of objects when equally-sized groups of objects are combined or arranged in arrays up to 10 by 10. Students will represent multiplication facts using various approaches such as repeated addition, equal-sized groups, arrays, area models, equal jumps on a number line, and skip counting. The lesson also supports recall of multiplication facts up to 10 by 10 and their corresponding division facts, promoting efficiency and accuracy in whole number computations.

Learning Objectives

  • Determine the total number of objects when equally-sized groups of objects are combined or arranged in arrays up to 10 by 10.
  • Represent multiplication facts using repeated addition, equal-sized groups, arrays, area models, equal jumps on a number line, and skip counting.
  • Recall multiplication facts up to 10 by 10 with automaticity and recall the corresponding division facts.

Success Criteria

  • Students can calculate the total number of objects in equal groups or arrays up to 10 by 10.
  • Students can represent multiplication facts using at least two different strategies such as arrays and repeated addition.
  • Students can recall multiplication facts up to 10 by 10 and their related division facts without hesitation.

Prerequisite Knowledge

Students should understand the concept of equal groups and basic addition. They should be familiar with counting by ones and have some experience with simple multiplication as repeated addition.

Key Vocabulary

  • Equal groups
  • Array
  • Multiplication fact
  • Repeated addition
  • Area model
  • Number line
  • Skip counting
  • Automaticity
  • Division fact

Materials and Resources

  • Counters or small objects for grouping (e.g., cubes, buttons)
  • Grid paper or printed 10 by 10 arrays
  • Whiteboard and markers
  • Number line visuals
  • Multiplication fact charts

Teacher Preparation

  • Prepare sets of counters grouped in equal sizes up to 10.
  • Prepare visual aids showing arrays up to 10 by 10.
  • Prepare number lines marked for skip counting.
  • Prepare multiplication fact charts for reference.

Detailed Lesson Notes

Understanding Equal Groups and Arrays

Equal groups are collections where each group has the same number of objects. Arrays are arrangements of objects in rows and columns, forming a rectangular pattern. Both models help visualize multiplication as combining equal groups or counting objects arranged in rows and columns. For example, 3 groups of 4 objects each can be arranged as 3 rows with 4 objects in each row, making an array of 3 by 4.

Representing Multiplication Facts Using Various Approaches

Multiplication facts can be represented in multiple ways: - Repeated addition: Adding the same number multiple times (e.g., 4 + 4 + 4 = 12). - Equal-sized groups: Counting the total objects in groups of the same size. - Arrays: Visualizing objects arranged in rows and columns. - Area models: Using length and width to find total units (like an array). - Equal jumps on a number line: Moving forward equal steps repeatedly. - Skip counting: Counting by a number repeatedly (e.g., counting by 4s). These approaches help students understand the concept of multiplication deeply and connect it to addition and counting.

Recalling Multiplication and Corresponding Division Facts

Automaticity in multiplication means recalling facts quickly without hesitation. For example, knowing that 6 × 7 = 42 immediately. Corresponding division facts relate multiplication and division, such as 42 ÷ 7 = 6 and 42 ÷ 6 = 7. Understanding this relationship helps students solve problems efficiently and check their work.

Common Misconceptions and How to Address Them

- Misconception: Multiplication always makes a bigger number. Address by showing examples like 1 × 5 = 5 or 0 × 7 = 0. - Misconception: Arrays must be square. Clarify that arrays can be rectangular, such as 3 by 4 or 2 by 5. - Misconception: Skip counting is just counting by ones. Emphasize that skip counting jumps by equal intervals, like counting by 2s or 5s.

Teaching Strategies and Models

Use concrete materials like counters to build equal groups and arrays. Draw arrays on grid paper to visualize rows and columns. Use number lines to demonstrate equal jumps and skip counting. Encourage students to explain their reasoning and compare different strategies. Connect multiplication facts to real-life contexts, such as arranging chairs in rows or packaging items.

Worked Examples

Worked Example 1

Scenario

You have 4 groups of 5 counters each. How many counters do you have in total? Show your answer using repeated addition and an array.

Explanation

Each group has 5 counters, and there are 4 groups. Repeated addition adds 5 four times: 5 + 5 + 5 + 5 = 20. An array can be drawn with 4 rows and 5 columns, showing 20 counters in total.

Answer Guide

Total counters = 5 + 5 + 5 + 5 = 20. The array has 4 rows and 5 columns, so 4 × 5 = 20 counters.

Worked Example 2

Scenario

Draw an array for 3 groups of 7 objects. Write the multiplication fact and the corresponding division facts.

Explanation

The array has 3 rows (groups) and 7 columns (objects per group). The multiplication fact is 3 × 7 = 21. The corresponding division facts are 21 ÷ 7 = 3 and 21 ÷ 3 = 7.

Answer Guide

Array: 3 rows and 7 columns. Multiplication fact: 3 × 7 = 21. Division facts: 21 ÷ 7 = 3 and 21 ÷ 3 = 7.

Engage

Teacher Activity

Show students a collection of objects arranged in equal groups and ask them how they would find the total number of objects quickly.

Student Activity

Observe the objects and share ideas on how to count the total without counting each object one by one.

Explanation

This activity activates prior knowledge about grouping and counting, setting the stage for learning multiplication as repeated addition and arrays.

Examples

  • Students identify the number of groups and objects per group.
  • Students suggest adding or multiplying to find the total.

Explore

Teacher Activity

Provide students with counters and ask them to create equal groups and arrays up to 10 by 10. Have them count the total objects and record their findings.

Student Activity

Use counters to make equal groups and arrays, count the total objects, and write multiplication expressions to represent them.

Explanation

Hands-on exploration helps students connect concrete objects to multiplication expressions and understand the structure of arrays and equal groups.

Examples

  • Students create groups and arrays and correctly count total objects.
  • Students write multiplication expressions matching their arrangements.

Explain

Teacher Activity

Demonstrate representing multiplication facts using repeated addition, arrays, area models, number lines, and skip counting. Explain the relationship between multiplication and division facts.

Student Activity

Watch demonstrations and practice representing multiplication facts using different methods. Discuss how multiplication and division facts relate.

Explanation

Explicit teaching clarifies multiple ways to represent multiplication and reinforces the connection to division facts for efficient problem solving.

Examples

  • Students explain repeated addition as adding equal groups.
  • Students identify rows and columns in arrays as factors.
  • Students recognize division facts as the inverse of multiplication.

Elaborate

Teacher Activity

Present real-world problems involving equal groups and arrays, such as seating arrangements or packaging items. Guide students to solve using multiplication strategies learned.

Student Activity

Solve real-world multiplication problems using arrays, repeated addition, or skip counting. Explain their reasoning to peers.

Explanation

Applying skills to real-world contexts deepens understanding and shows the usefulness of multiplication strategies.

Examples

  • Students use arrays or repeated addition to solve problems.
  • Students explain their multiplication strategies clearly.

Evaluate

Teacher Activity

Ask students to demonstrate how to find the total number of objects in equal groups or arrays and represent the multiplication facts using at least two different methods.

Student Activity

Show understanding by solving problems, representing multiplication facts in multiple ways, and recalling multiplication and division facts.

Explanation

Assessment confirms students' mastery of determining totals in equal groups and arrays and their ability to represent and recall multiplication facts.

Examples

  • Students correctly calculate totals in equal groups and arrays.
  • Students represent multiplication facts using different methods.
  • Students recall multiplication and division facts accurately.

Classroom Activity

Use counters to make equal groups and arrays, count the total objects, and write multiplication expressions to represent them.

Guided Practice

Guided Practice 1

Prompt

If you have 4 groups of 6 objects, how many objects are there in total?

Teacher Answer Guide

4 groups × 6 objects = 24 objects in total.

Guided Practice 2

Prompt

Show how to represent 5 × 3 using repeated addition.

Teacher Answer Guide

5 × 3 is 3 added 5 times: 3 + 3 + 3 + 3 + 3 = 15.

Guided Practice 3

Prompt

What multiplication fact does an array with 7 rows and 2 columns represent?

Teacher Answer Guide

7 × 2 = 14.

Guided Practice 4

Prompt

What are the division facts related to 8 × 5 = 40?

Teacher Answer Guide

40 ÷ 8 = 5 and 40 ÷ 5 = 8.

Guided Practice 5

Prompt

Explain why skip counting is useful for multiplication.

Teacher Answer Guide

Skip counting helps find the total by counting equal jumps, making multiplication faster and easier to understand.

Independent Practice

  1. Foundational: If you have 5 groups with 2 objects in each group, how many objects do you have in total?
  2. Developing: Represent 6 × 4 using repeated addition and an array.
  3. Application: A classroom has 8 rows of chairs with 5 chairs in each row. How many chairs are there? Show your answer using skip counting.
  4. Analysis: Explain how multiplication and division facts are related using the example 7 × 3 = 21.
  5. Challenge: Create an array for 9 × 6 and write the multiplication and division facts. Then explain why arrays help in understanding multiplication.

Independent Practice Teacher Answer Key

  1. 1. 5 groups × 2 objects = 10 objects in total.
  2. 2. Repeated addition: 4 + 4 + 4 + 4 + 4 + 4 = 24. Array: 6 rows and 4 columns, total 24 objects.
  3. 3. Skip counting by 5 eight times: 5, 10, 15, 20, 25, 30, 35, 40. Total chairs = 40.
  4. 4. Multiplication fact 7 × 3 = 21 means 7 groups of 3 objects equal 21. The related division facts are 21 ÷ 7 = 3 and 21 ÷ 3 = 7, showing division undoes multiplication.
  5. 5. Array: 9 rows and 6 columns. Multiplication fact: 9 × 6 = 54. Division facts: 54 ÷ 9 = 6 and 54 ÷ 6 = 9. Arrays help visualize multiplication by showing groups and total objects, making it easier to understand the concept.

Guiding Questions

  • How do equal groups help you find the total number of objects?
  • What does each factor in a multiplication expression represent in an array?
  • How can repeated addition and skip counting show multiplication?
  • What is the relationship between multiplication and division facts?

Common Misconceptions

  • Multiplication always makes a bigger number; sometimes multiplying by 1 or 0 does not increase the number.
  • Arrays must be square; arrays can be rectangular with different numbers of rows and columns.
  • Skip counting is just counting by ones; skip counting jumps by equal intervals, not by ones.

Differentiation

Support and Intervention

Use counters and visual aids for students needing concrete examples. Provide step-by-step guidance for forming arrays and writing multiplication expressions.

English-Language Learner Support

Use pictures and gestures to explain equal groups and arrays. Provide vocabulary cards with key terms and definitions.

Advanced and Extension

Challenge students to create and solve word problems involving arrays up to 10 by 10. Encourage students to explain the relationship between multiplication and division facts in their own words.

Assessment

  • Observe students as they create equal groups and arrays and explain their reasoning.
  • Ask students to represent multiplication facts using at least two different methods during guided practice.
  • Write a multiplication fact for an array of 5 rows and 4 columns and explain what each number represents.
  • Explain the relationship between a multiplication fact and its corresponding division facts.
  • Solve a set of problems involving equal groups and arrays up to 10 by 10.
  • Represent multiplication facts using repeated addition, arrays, and skip counting.
  • Recall multiplication facts up to 10 by 10 and their corresponding division facts.

Answer Guide

  • If you have 4 groups of 6 objects, how many objects are there in total?
    Answer: 4 groups × 6 objects = 24 objects in total.
  • Show how to represent 5 × 3 using repeated addition.
    Answer: 5 × 3 is 3 added 5 times: 3 + 3 + 3 + 3 + 3 = 15.
  • What multiplication fact does an array with 7 rows and 2 columns represent?
    Answer: 7 × 2 = 14.
  • What are the division facts related to 8 × 5 = 40?
    Answer: 40 ÷ 8 = 5 and 40 ÷ 5 = 8.
  • Explain why skip counting is useful for multiplication.
    Answer: Skip counting helps find the total by counting equal jumps, making multiplication faster and easier to understand.

Real-Life Application

Encourage students to find examples of equal groups or arrays at home, such as rows of chairs or sets of utensils, and write multiplication facts to represent them.

Homework or Home Connection

  • Encourage students to find examples of equal groups or arrays at home, such as rows of chairs or sets of utensils, and write multiplication facts to represent them.

Lesson Summary

Students learned to determine the total number of objects in equally-sized groups and arrays up to 10 by 10. They explored multiple ways to represent multiplication facts, including repeated addition, arrays, area models, number lines, and skip counting. The lesson emphasized recalling multiplication facts up to 10 by 10 and understanding their relationship to division facts, supporting efficient and accurate problem solving.

Teacher Notes

Use the exact standards alignment and retrieved-source provenance stored with this enrichment.

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