Chapter 1 · Revising and improving
Lesson 1.2 · Four operations with parentheses
Hua's Classroom for Shanghai Maths — One Lesson One Exercise (English edition, pages 4–6).
Lesson Alignment
How this Shanghai Maths lesson connects to learning goals, Common Core, and Eureka Math.
Learning Objectives
Students will be able to:
- 01Calculate expressions with parentheses using the correct order. (Question 1)
- 02Compare expressions with and without brackets. (Question 2)
- 03Write number sentences with brackets to match a story. (Question 3)
- 04Solve multi-step problems that need grouping. (Question 4–5)
Common Core Standards
| Code | Standard (focus for this lesson) |
|---|---|
| 3.OA.D.8 | Two-step (and multi-step) problems; use grouping symbols. |
| 3.NBT.A.2 | Add and subtract within 1000. |
| 3.OA.B.5 | Properties of operations. |
Eureka Math Correspondence
| Shanghai Maths | Focus | Eureka Math |
|---|---|---|
| Q1–2 | Parentheses change value | G3 M1 / M3 |
| Q3–4 | Write grouped sentences | G3 M2 / M3 |
| Applications | Pack / ticket stories | G3 M3 application |
Core Concepts
Parentheses group operations — calculate inside brackets first.
Brackets First
Step 1
Work inside parentheses ( ) first.Step 2
Then × and ÷ (left to right).Step 3
Then + and − (left to right).| Expression | Think | Value |
|---|---|---|
| $(12 + 8) imes 3$ | $20 imes 3$ | $60$ |
| $12 + 8 imes 3$ | $12 + 24$ | $36$ |
| $(30 - 6) \div 4$ | $24 \div 4$ | $6$ |
With / Without Brackets
Same numbers, different grouping → different answers. Brackets show which part to do first.
Common error: ignoring brackets and doing × before + everywhere without checking for ( ).
Stories with Grouping
When a story has two steps that must stay together, write brackets in the number sentence.
Key Terms & Definitions (Reference)
Quick glossary for this lesson.
| Term | Definition |
|---|---|
| Parentheses | Brackets ( ) that group part of a calculation. |
| Order of operations | Rules for which operation to do first. |
| Number sentence | An equation showing a calculation. |
Key Answers
Quick reference for this lesson’s exercise answers.
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