Chapter 2 · Multiplying by a one-digit number
Lesson 2.1 · Multiplying whole tens and whole hundreds (1)
Hua's Classroom for Shanghai Maths — One Lesson One Exercise (English edition, pages 16–17).
Lesson Alignment
How this Shanghai Maths lesson connects to learning goals, Common Core, and Eureka Math.
Learning Objectives
Students will be able to:
- 01Calculate products of whole tens/hundreds × a one-digit number with reasoning. (Question 1)
- 02Explain using tens/hundreds language and count zeros in products. (Question 2)
- 03Compare and match related products. (Question 3–4)
- 04Solve one- and two-step application problems. (Question 6–7)
Common Core Standards
| Code | Standard (focus for this lesson) |
|---|---|
| 3.NBT.A.3 | Multiply one-digit whole numbers by multiples of 10. |
| 3.OA.A.3 | Multiply to solve word problems. |
| 3.OA.D.8 | Two-step word problems. |
Eureka Math Correspondence
| Shanghai Maths | Focus | Eureka Math |
|---|---|---|
| Q1–2 | Pattern & place-value language | G3 M3 Topic C–D |
| Q3–5 | Compare / unknown factor | G3 M1 / M3 |
| Applications | Mass, pages, packs | G3 M3 application |
Core Concepts
Multiply whole tens and whole hundreds by a one-digit number using place-value reasoning.
Whole Tens / Hundreds Pattern
First multiply the non-zero digits, then attach the zeros:
| Think | Example |
|---|---|
| $4 \times 7 = 28$ | $4 \times 70 = 280$, $4 \times 700 = 2800$ |
| $5 \times 3 = 15$ | $50 \times 3 = 150$, $500 \times 3 = 1500$ |
| $6 \times 9 = 54$ | $60 \times 9 = 540$, $6 \times 90 = 540$ |
Language: “6 multiplied by 3 tens is 18 tens” → $6 \times 30 = 180$.
Zeros in the Product
- Whole tens × one-digit → usually one trailing zero (unless the basic fact ends in 0).
- Whole hundreds × one-digit → usually two trailing zeros — but check the basic product (e.g. $5 \times 2 = 10$).
True/false trap: “whole hundreds × one-digit always ends with 2 zeros” is not always true.
Compare Products
Use $=$, $>$, $<$ after finding both products, or reason with place value ($9 \times 50 = 90 \times 5$).
Applications
- Pack mass: grams → kilograms ($500\ \text{g} \times 8 = 4000\ \text{g} = 4\ \text{kg}$).
- “Times as many” pages / prices with one-digit multipliers.
Key Terms & Definitions (Reference)
Quick glossary for this lesson.
| Term | Definition |
|---|---|
| Whole tens | A multiple of 10 (e.g. 30, 70). |
| Whole hundreds | A multiple of 100 (e.g. 500, 800). |
| Factor / Product | Numbers multiplied / the result. |
| Trailing zeros | Zeros at the end of a product. |
Key Answers
Quick reference for this lesson’s exercise answers.
Key answers
- Calculate with reasoning
- $4×7=28$, $4×70=280$, $4×700=2800$
- $5×3=15$, $50×3=150$, $500×3=1500$
- $6×9=54$, $60×9=540$, $6×90=540$
- Fill in the brackets
- (1) $240$; $4×60=240$. $1000$; $5×200=1000$
- (2) $3$ tens; $18$ tens; $180$
- (3) $3$ zeros ($800×5=4000$)
- Compare: (1) $=$ (2) $>$ (3) $<$ (4) $<$ (5) $<$ (6) $=$
- Match: $5×70→350$; $500×7→3500$; $7000×5→35000$; $5×7→35$
- Fill suitable numbers: (1) $400$ (2) $2$ (3) $5$ (4) $4$
- True / false: (1) $×$ (false) (2) $✓$ (true; $270<280$)
- Number sentences: (1) $600×3=1800$ (2) $400×8+8=3208$
- Applications: (1) $4$ kg (2) page $81$
- Extension: $2400$ yuan