CCSS.MATH.4.NBT.B.5✓ California Department of Education (CDE) AlignedAcademic Year 2026–27
Multi-Digit Multiplication: Area Models & Partial Products
Use geometric area grids and partial products to compute 4-digit by 1-digit and 2-digit by 2-digit products.
Why It Matters:Essential for square footage estimation, manufacturing production schedules, and retail bulk pricing.
Curated Video Instruction
● Verified Active EmbedSTEP-BY-STEP PROOF
Worked Example
Calculate 34 * 28 using the area model / partial products:
1
Decompose numbers into tens and ones
34 = 30 + 4; 28 = 20 + 8
Create a 2x2 grid representing the four partial products.
2
Calculate the four partial products
30 * 20 = 600; 30 * 8 = 240; 4 * 20 = 80; 4 * 8 = 32
Multiply each expanded component.
3
Sum the four partial products
600 + 240 + 80 + 32 = 952
Combine all partial areas.
✓Verification Check
Check using standard vertical algorithm: 34 * 28 = 952.
34 * 28 = 952
•
952 = 952 (Verified)
⚠️ Common Pitfalls & Misconceptions
Multiplying only ones by ones and tens by tens
✗ Thinking 34 * 28 = (30 * 20) + (4 * 8) = 600 + 32 = 632✓ Every term must be distributed: (30+4)*(20+8) yields 4 products
Omitting cross-products (30*8 and 4*20) loses over 300 from the true value.
INTERACTIVE DRILLS
Guided Practice
Practice Question1 of 1
Step-by-step Feedback
What is 42 * 16?
MASTERY BENCHMARK
Official Assessment Quiz
Formal Assessment
Multi-Digit Multiplication: Area Models & Partial Products
Passing Criteria:70% or higher
Question 1 of 1
What is 324 * 6?
Education to Career Navigation
Where This Lesson Leads
Civil Contractors and Event Coordinators calculate bulk resource materials.