Lesson Plan
Rows, Columns, Area!
Students will draw rows and columns on incomplete arrays to accurately determine the area of a rectangle.
Understanding area is a fundamental skill for many real-world applications, from home projects to careers in design and architecture.
Audience
4th Grade
Time
30 minutes
Approach
Hands-on drawing and guided practice.
Materials
Warm-Up: 'Complete the Array!' worksheet Warm-Up Worksheet, Slide Deck: 'Rows, Columns, Area!' Slide Deck, Worksheet: 'Area Array Challenge' Area Array Challenge Worksheet, Answer Key: 'Area Array Challenge Answer Key' Area Array Challenge Answer Key, Pencils, and Rulers (optional)
Prep
Prepare Materials
10 minutes
- Review the Warm-Up Worksheet, Slide Deck, Area Array Challenge Worksheet, and Area Array Challenge Answer Key.
- Print copies of the Warm-Up Worksheet (one per student).
- Print copies of the Area Array Challenge Worksheet (one per student).
- Ensure projector/interactive whiteboard is ready for the Slide Deck.
Step 1
Warm-Up: Complete the Array!
5 minutes
- Distribute the Warm-Up Worksheet.
- Instruct students to complete the incomplete arrays by drawing the missing rows and columns and then find the total number of squares.
- Briefly review answers as a class, asking students to share their strategies.
Step 2
Introduction to Area with Incomplete Arrays
10 minutes
- Project the Slide Deck starting with the 'Learning Target' slide.
- Read the learning target and success criteria aloud: Learning Target: I can draw rows and columns to determine the area of a rectangle given an incomplete array. Success Criteria: I can identify the missing rows and columns, draw them accurately, and calculate the total area.
- Use the Slide Deck to explain how drawing missing rows and columns helps visualize and calculate area.
- Guide students through examples on the slides, encouraging them to participate in identifying dimensions and calculating area.
Step 3
Guided Practice: Area Array Challenge
10 minutes
- Distribute the Area Array Challenge Worksheet.
- Instruct students to work independently or in pairs to complete the worksheet.
- Circulate around the room, providing support and clarification as needed.
- Remind students to draw clearly and use the length x width formula once the array is complete.
Step 4
Wrap-Up & Review
5 minutes
- Bring the class back together.
- Review a few problems from the Area Array Challenge Worksheet using the Area Array Challenge Answer Key to clarify any misconceptions.
- Reiterate the learning target and success criteria. Ask students to give a thumbs up, down, or sideways to indicate their confidence in meeting the criteria.
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Slide Deck
Rows, Columns, Area!
Let's uncover the secrets of shape size!
Welcome students and introduce the exciting lesson ahead. Briefly mention that today's lesson is about understanding area in a fun, visual way.
Our Goal Today
Learning Target: I can draw rows and columns to determine the area of a rectangle given an incomplete array.
Success Criteria:
- I can identify the missing rows and columns.
- I can draw them accurately.
- I can calculate the total area.
Read the learning target and success criteria clearly. Ask students to think about what each part means. Encourage them to set a goal to achieve these by the end of the lesson.
What is Area?
Area is the amount of space a flat shape covers.
We usually measure area in square units!
Think: How many squares fit inside?
Briefly review what area means. Ask students for examples of when they might need to know the area of something in real life (e.g., painting a wall, buying carpet).
Mystery Shapes: Incomplete Arrays!
Sometimes, you might see a rectangle where some of the rows and columns aren't fully drawn.
It's like a puzzle! But don't worry, we have a trick!
Introduce the concept of an incomplete array. Explain that sometimes we don't see all the squares, but we can still figure out the total. This is like being a detective!
Strategy 1: Draw Those Lines!
Look closely at the array.
- See where the lines stop?
- Gently extend them across the shape!
- Do this for both the rows (going across) and columns (going up and down).
Now your array is complete!
Explain the first strategy: drawing the missing lines. Emphasize using the existing lines as guides. Demonstrate on a whiteboard or interactive screen if possible.
Let's Practice Together!
Look at this rectangle:
[Image of a 3x4 incomplete array with only outer squares drawn]
- Draw the missing rows and columns.
- Count how many rows there are.
- Count how many columns there are.
- Multiply rows x columns to find the area!
What do you get?
Show a simple example. Guide students to first draw the lines mentally or with a finger, then count the rows and columns. Then, use multiplication.
Your Turn! Area Array Challenge
Now it's time to put your skills to the test!
- You'll get a worksheet with more incomplete arrays.
- Remember to draw the missing lines carefully.
- Count your rows and columns.
- Calculate the area!
Good luck, area detectives!
Transition to independent practice. Explain the worksheet and encourage them to apply the strategies learned. Remind them they can ask for help.
Warm Up
Warm-Up: Complete the Array!
Instructions: Draw the missing rows and columns to complete each array. Then, write the area of the rectangle in square units.
Problem 1
![Incomplete array 1: A 2x3 rectangle with only the outer lines and corners filled, leaving the internal grid lines to be drawn.]
Area:
Problem 2
![Incomplete array 2: A 3x2 rectangle with only the outer lines and corners filled, leaving the internal grid lines to be drawn.]
Area:
Problem 3
![Incomplete array 3: A 4x3 rectangle with only the outer lines and corners filled, leaving the internal grid lines to be drawn.]
Area:
Worksheet
Area Array Challenge
Instructions: For each incomplete array, carefully draw the missing rows and columns to complete the rectangle. Then, count the total number of rows and columns, and calculate the area of the rectangle in square units.
Problem 1
![Incomplete array 1: A 3x5 rectangle with only the outer lines and corners filled, leaving the internal grid lines to be drawn.]
Rows:
Columns:
Area:
Problem 2
![Incomplete array 2: A 4x2 rectangle with only the outer lines and corners filled, leaving the internal grid lines to be drawn.]
Rows:
Columns:
Area:
Problem 3
![Incomplete array 3: A 5x3 rectangle with only the outer lines and corners filled, leaving the internal grid lines to be drawn.]
Rows:
Columns:
Area:
Problem 4
![Incomplete array 4: A 2x6 rectangle with only the outer lines and corners filled, leaving the internal grid lines to be drawn.]
Rows:
Columns:
Area:
Problem 5
![Incomplete array 5: A 3x4 rectangle with only the outer lines and corners filled, leaving the internal grid lines to be drawn.]
Rows:
Columns:
Area:
Answer Key
Area Array Challenge Answer Key
Here are the answers and thought processes for the Area Array Challenge Worksheet:
Problem 1
Thought Process:
- Observe the incomplete 3x5 array. The existing markings show 3 rows and 5 columns.
- Mentally (or physically, if using a pencil) complete the internal lines to form a grid of individual squares.
- Count the total number of rows (3) and the total number of columns (5).
- Multiply the number of rows by the number of columns: 3 x 5 = 15.
Rows: 3
Columns: 5
Area: 15 square units
Problem 2
Thought Process:
- Observe the incomplete 4x2 array. The existing markings show 4 rows and 2 columns.
- Mentally (or physically) complete the internal lines.
- Count the total number of rows (4) and the total number of columns (2).
- Multiply the number of rows by the number of columns: 4 x 2 = 8.
Rows: 4
Columns: 2
Area: 8 square units
Problem 3
Thought Process:
- Observe the incomplete 5x3 array. The existing markings show 5 rows and 3 columns.
- Mentally (or physically) complete the internal lines.
- Count the total number of rows (5) and the total number of columns (3).
- Multiply the number of rows by the number of columns: 5 x 3 = 15.
Rows: 5
Columns: 3
Area: 15 square units
Problem 4
Thought Process:
- Observe the incomplete 2x6 array. The existing markings show 2 rows and 6 columns.
- Mentally (or physically) complete the internal lines.
- Count the total number of rows (2) and the total number of columns (6).
- Multiply the number of rows by the number of columns: 2 x 6 = 12.
Rows: 2
Columns: 6
Area: 12 square units
Problem 5
Thought Process:
- Observe the incomplete 3x4 array. The existing markings show 3 rows and 4 columns.
- Mentally (or physically) complete the internal lines.
- Count the total number of rows (3) and the total number of columns (4).
- Multiply the number of rows by the number of columns: 3 x 4 = 12.
Rows: 3
Columns: 4
Area: 12 square units