3.1 Number and Algebra 數與代數

Directed Numbers and the Number Line 有向數及數線

• gMath: 有向數 Directed Numbers

• Addition of Directed Numbers - Counters Model ,
  Subtraction of Directed Numbers - Counters Model

• Addition of Integers ,
  Subtraction of Integers (ver. 1) ,
  Subtraction of Integers (ver. 2)

• Addition of Directed Numbers - The Elevator Model ,
  Subtraction of Directed Numbers - The Elevator Model

• Directed Number Multiplication

• Speed Time model for multiplication of directed numbers

Approximation and Errors 近似與誤差 

• gMath: 近似與誤差 Approximation & Errors

• Errors in Measurement 

• 量度的誤差

• Rounding Off

Using Percentages 百分法

• gMath: 百分法(1) Percentage(1)

• Comparing Two Quantities by Percentage

• Percentages and Their Applications
  百分數及其應用

• Percentages: Discount, Profit and Loss

• 百分數：折扣、盈利與虧損

More about Percentages 續百分法

• gMath: 百分法(2) Percentage(2)

Rate and Ratio 率及比

• gMath: 比 Ratios

Formulating Problems with Algebraic Language 以代數語言建立問題

• gMath: 配對代數式 Algebraic Expression Matching

• gMath: 合併同類項測驗 Quiz on Combining Like Terms

• Triangular Number 三角形數

• 數列的第n項：測驗

Manipulations of Simple Polynomials 簡易多項式的運算

• gMath: 多項式的運算 Introduction to Polynomials

Laws of Integral Indices 整數指數律

• gMath: 指數記數法測驗 | Quiz on Index Notation

• gMath: 整數指數定律 Laws of Indices

Identities 恒等式

• gMath: 恆等式、因式分解 Identities & Factorization

Factorization of Simple Polynomials 簡易多項式的因式分解

• gMath: 恆等式、因式分解 Identities & Factorization

Linear Equations in One Unknown 一元一次方程

• gMath: 解方程的含意 Meaning of Solving Equations

• gMath: 解「一步」一次方程：測驗(1) Quiz on Solving One-step Linear Equations (1)

• gMath: 解「一步」一次方程：測驗(2) Quiz on Solving One-step Linear Equations (2)

Linear Equations in Two Unknowns 二元一次方程

• gMath: 聯立二元一次方程 Simultaneous Linear Equations

• Graphing Linear Equations in 2 Unknowns

Linear Inequalities in One Unknown 一元一次不等式

• gMath: 不等式 Inequalities