Chapter 2 · Multiplying and dividing by two-digit numbers
Lesson 2.5 · Multiplying a two-digit number by a two-digit number (2)
Hua's Classroom for Shanghai Maths — One Lesson One Exercise (English edition, pages 34–36).
Lesson Alignment
How this Shanghai Maths lesson connects to learning goals, Common Core, and Eureka Math.
Learning Objectives
Students will be able to:
- 01Use column method for two-digit × two-digit. (Question 1)
- 02Write number sentences from language. (Question 2)
- 03Solve seating and arrangement puzzles. (Question 3–4)
Common Core Standards
| Code | Standard (focus for this lesson) |
|---|---|
| 4.NBT.B.5 | Multiply with standard algorithm. |
| 3.OA.A.3 | Word problems. |
Eureka Math Correspondence
| Shanghai Maths | Focus | Eureka Math |
|---|---|---|
| Column | 48×65 | G4 M3 |
| Seating | Rows & seats | G3 M3 |
Core Concepts
Column multiply; inverse stories (take out half in 10 steps).
Column Method
Partial products: ones × both digits of second factor, then tens × both; add.
Number Sentences
“Product of two eighty-nines” → $89 \times 89$; greatest two-digit sum × 9.
Seating Problems
Row/seat position from left and right → seats per row → total capacity.
Key Terms & Definitions (Reference)
Quick glossary for this lesson.
| Term | Definition |
|---|---|
| Partial product | Product of one digit and part of the other factor. |
| Column method | Vertical multiplication layout. |
Key Answers
Quick reference for this lesson’s exercise answers.
1. Column fill-in
$48\times65=3120$ (ones digit $5$, tens digit $6$)
2. Column method
- $13\times22=286$;\; $44\times73=3212$;\; $77\times68=5236$
3. Corrections
- $44\times55=2420$;\; $37\times12=444$;\; $26\times98=2548$
4. Number sentences
- $89\times89=7921$
- $(99+99)\div9=22$
5. Application
- $212$ Grade 5 pupils
- $1028$ yuan; yes ($588<600$)
- $704$ seats
- Whole road $1280\,\text{m}$
6. Enhancement
- Squares: $121,144,169,196,225,256,289,324,361$
- $\times11$: $121,132,143,154,165,176,187,198,209$