Number Foundations: Place Value, Addition and Subtraction | 数字基础：位值、加法与减法

📚 Number Foundations: Place Value, Addition and Subtraction | 数字基础：位值、加法与减法

Understanding place value and the four basic operations is the first step towards success in IGCSE Mathematics. Whether you are working with small whole numbers or preparing for multi-step problems, a strong grasp of tens, ones, addition and subtraction builds the foundation for fractions, decimals, algebra and beyond.

理解位值和四种基本运算是 IGCSE 数学成功的第一步。无论你是在处理较小的整数，还是准备多步应用题，牢固掌握十位、个位、加法和减法都能为分数、小数、代数以及更高层次的内容奠定基础。

1. Place Value and Base-10 Blocks | 位值与十进位积木

In our decimal system, every digit has a place value. The rightmost digit represents ones, the next digit to the left represents tens, and then hundreds. For example, in 362, the 2 means 2 ones, the 6 means 6 tens (60), and the 3 means 3 hundreds (300). This means 362 = 300 + 60 + 2.

在我们的十进制系统中，每个数字都有位值。最右边的数字代表个位，左边下一位代表十位，再左边是百位。例如在 362 中，2 表示 2 个一，6 表示 6 个十（60），3 表示 3 个百（300）。这意味着 362 = 300 + 60 + 2。

Base-10 blocks make this visible: a flat represents 100, a rod represents 10, and a small cube represents 1. To build 243, you would use 2 flats, 4 rods and 3 unit cubes. This visual approach is especially useful when moving to multiplication and division later.

十进位积木可以使这一点可视化：一个百板代表 100，一个十棒代表 10，一个小立方体代表 1。要表示 243，你会用 2 个百板、4 个十棒和 3 个单位立方体。这种可视化方法对之后学习乘法和除法特别有用。

2. Reading and Writing Numbers in Words | 用文字读写数字

In IGCSE exams, you may be asked to write a numeral in words or convert words into digits. Numbers from 21 to 99 often use a hyphen, such as twenty-one, forty-seven and ninety-nine. Round hundreds like 600 are written as ‘six hundred’, and numbers like 605 are ‘six hundred and five’.

在 IGCSE 考试中，你可能会被要求将数字写成英文单词，或将英文单词转换成数字。21 到 99 的数字通常使用连字符，例如 twenty-one、forty-seven 和

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