Chapter 4 · Dividing by a one-digit number
Lesson 4.5 · Dividing a two-digit number by a one-digit number (4)
Hua's Classroom for Shanghai Maths — One Lesson One Exercise (English edition, pages 73–75).
Lesson Alignment
How this Shanghai Maths lesson connects to learning goals, Common Core, and Eureka Math.
Learning Objectives
Students will be able to:
- 01Divide two-digit ÷ one-digit fluently (mental + written).
- 02Translate language into division sentences (“What is 82 ÷ 2?”).
- 03Reason through the enhancement mouse / every-other puzzle.
Common Core Standards
| Code | Standard (focus for this lesson) |
|---|---|
| 3.OA.A.2 | Interpret whole-number quotients. |
| 3.OA.A.3 | Multiply/divide within 100 to solve word problems. |
| 3.OA.B.5 | Apply properties of operations. |
| 3.OA.B.6 | Understand division as unknown-factor. |
| 3.OA.C.7 | Fluently multiply and divide within 100. |
| 3.OA.D.8 | Two-step word problems. |
Eureka Math Correspondence
| Shanghai Maths | Focus | Eureka Math |
|---|---|---|
| Fluency | ÷ within 100+ | G3 M1 |
| Enhancement | Logical sequencing | Problem solving |
Core Concepts
Build fluency and language; stretch with a multi-step enhancement puzzle.
Fluency Practice
Mental sets and column practice for two-digit ÷ one-digit.
Write Number Sentences
From words → equation → calculate.
Enhancement Puzzle
Cat eating every other mouse in three passes — white mouse chooses a safe place (logic + skip-counting / odds).
Key Terms & Definitions (Reference)
Quick glossary for this lesson.
| Term | Definition |
|---|---|
| Dividend | The number being divided. |
| Divisor | The number you divide by. |
| Quotient | The result of division. |
| Remainder | What is left after equal groups are made. |
| Relationship | dividend = divisor × quotient + remainder |
Key Answers
Quick reference for this lesson’s exercise answers.
1. Mental calculation
- $30\div3=10$,\; $40\div2=20$,\; $80\div4=20$,\; $60\div2=30$,\; $500\div5=100$
- $39\div3=13$,\; $48\div2=24$,\; $84\div4=21$,\; $68\div2=34$,\; $6000\div3=2000$
2. Calculate and compare
- $96\div3=32$,\; $92\div3=30\ldots2$,\; $96\div6=16$,\; $92\div6=15\ldots2$
3. Column method
- $83\div4=20\ldots3$,\; $81\div2=40\ldots1$,\; $65\div6=10\ldots5$,\; $90\div4=22\ldots2$
- $96\div9=10\ldots6$,\; $53\div5=10\ldots3$,\; $75\div7=10\ldots5$,\; $87\div8=10\ldots7$
4. Division charts
- $480\div4=120$,\; $480\div6=80$,\; $480\div8=60$
- $3000\div3=1000$,\; $3000\div5=600$,\; $3000\div6=500$
5. Related operations
- $2\times200=400$,\; $400\div2=200$;\; $300\times3=900$,\; $900\div3=300$;\; $4\times500=2000$,\; $2000\div4=500$
6. Write the number sentences and calculate
- $82\div2=41$
- $900\div3=300$
- $640\div2=320$
- $320\div4=80$
7. Application problems
- $180$ cubic metres per hour
- $75$ flies each in $3$ hours;\; $50$ flies per hour for $2$ dragonflies;\; $25$ flies per dragonfly per hour
8. Enhancement
The white mouse stood in the 8th place.