Calculate: 23 × 14
Using the area model, decompose into tens and ones.
Area Model Multiplication: A visual method that breaks down multiplication into smaller, more manageable parts using rectangular arrays.
23 = 20 + 3 (2 tens and 3 ones)
14 = 10 + 4 (1 ten and 4 ones)
20 × 10 = 200
3 × 10 = 30
20 × 4 = 80
3 × 4 = 12
200 + 30 + 80 + 12 = 322
23 × 14 = 322
• Decomposition Rule: Break numbers into tens and ones
• Multiplication Rule: Multiply each part separately
• Addition Rule: Sum all partial products
Calculate: 45 × 26
Try solving this using the area model before checking the solution.
Partial Products: Each section of the area model represents a partial product that contributes to the total.
45 = 40 + 5 (4 tens and 5 ones)
26 = 20 + 6 (2 tens and 6 ones)
40 × 20 = 800
5 × 20 = 100
40 × 6 = 240
5 × 6 = 30
800 + 100 + 240 + 30 = 1,170
45 × 26 = 1,170
• Systematic Approach: Work through each section methodically
• Place Value Accuracy: Maintain correct place value during multiplication
• Verification: Check addition of partial products
Tom has 38 boxes of markers. Each box contains 24 markers. How many markers does Tom have in total?
Use the area model to solve this problem.
Word Problems: Area model helps visualize multiplication in practical contexts and builds problem-solving skills.
We need to find: 38 × 24
Decompose: 38 = 30 + 8, 24 = 20 + 4
30 × 20 = 600
8 × 20 = 160
30 × 4 = 120
8 × 4 = 32
600 + 160 + 120 + 32 = 912
Tom has 912 markers in total.
• Problem Translation: Convert word problems to multiplication
• Visualization: Use area model to represent the situation
• Contextual Answer: Include units in final answer
Area Model: A rectangular visual representation showing how multiplication works by breaking numbers into parts
Partial Products: Individual multiplication results that are added together
Distributive Property: The mathematical foundation that makes area model multiplication work
Place Value: Understanding that digits have different values based on their position
- Analyze the numbers: Identify tens and ones in each factor
- Create the grid: Set up a rectangle divided into four sections
- Fill in sections: Multiply each part of the first number by each part of the second
- Calculate: Find the area of each section
- Combine: Add all partial products to get the final answer
• Decomposition Rule: Always break numbers into place values
• Multiplication Rule: Tens × tens, tens × ones, ones × tens, ones × ones
• Addition Rule: Sum all partial products for final answer
• Verification Rule: Check work by estimating or using standard algorithm
= (20+3)(10+4)
= 200+80+30+12
= 322
= (40+5)(20+6)
= 800+240+100+30
= 1,170
= (30+8)(20+4)
= 600+120+160+32
= 912
Calculate: 67 × 38
Apply the area model with careful attention to place value.
Large Numbers: The area model works for any size numbers by extending the decomposition principle.
67 = 60 + 7 (6 tens and 7 ones)
38 = 30 + 8 (3 tens and 8 ones)
60 × 30 = 1,800
7 × 30 = 210
60 × 8 = 480
7 × 8 = 56
1,800 + 210 + 480 + 56 = 2,546
67 × 38 = 2,546
• Consistent Place Value: Maintain correct place value during multiplication
• Accurate Addition: Carefully add all partial products
• Verification: Double-check calculations for larger numbers
A school has 42 classrooms. Each classroom has 28 desks. How many desks are there in total?
Use the area model to solve and explain your thinking.
Problem Solving: Area model helps visualize multiplication in practical contexts and builds problem-solving skills.
We need to find: 42 × 28
Decompose: 42 = 40 + 2, 28 = 20 + 8
40 × 20 = 800
2 × 20 = 40
40 × 8 = 320
2 × 8 = 16
800 + 40 + 320 + 16 = 1,176
The school has 1,176 desks in total.
• Problem Translation: Convert word problems to multiplication
• Visualization: Use area model to represent the situation
• Contextual Answer: Include units in final answer
Area Model: A rectangular visual representation showing how multiplication works by breaking numbers into parts
Partial Products: Individual multiplication results that are added together
Distributive Property: The mathematical foundation that makes area model multiplication work
Place Value Decomposition: Breaking numbers into their component parts based on their position
- Analyze the numbers: Identify tens and ones in each factor
- Create the grid: Set up a rectangle divided into four sections
- Fill in sections: Multiply each part of the first number by each part of the second
- Calculate: Find the area of each section
- Combine: Add all partial products to get the final answer
• Decomposition: 2-digit number = tens + ones (e.g., 34 = 30 + 4)
• Area Model: (a+b)(c+d) = ac + ad + bc + bd
• Partial Products: Multiply each part separately, then add
• Verification: Estimate to check reasonableness of answer
1. Decompose both numbers into tens and ones
2. Create a 2×2 grid
3. Fill each cell with partial products
4. Add all partial products
• Visual understanding of multiplication
• Connects to distributive property
• Builds foundation for algebra
• Helps with mental math
This is the distributive property
Applied in area model multiplication