Year 9 OCR Maths: Vocabulary & Terminology Quick Memorisation Guide | 9年级OCR数学：词汇术语速记指南

📚 Year 9 OCR Maths: Vocabulary & Terminology Quick Memorisation Guide | 9年级OCR数学：词汇术语速记指南

Mastering key mathematical vocabulary is essential for success in Year 9 OCR Maths. Understanding terms like factor, coefficient, gradient, and congruent not only helps you solve problems but also allows you to communicate your reasoning clearly. This guide provides a bilingual (English-Chinese) collection of essential terms, each paired with a memory tip to make memorisation fast and lasting.

掌握关键的数学词汇是Year 9 OCR数学成功的基石。理解因数、系数、梯度、全等等术语不仅有助于解题，还能让你清晰地表达推理。本指南提供了一份中英双语的必备术语集，每个术语都配有记忆技巧，帮你实现快速而持久的记忆。

1. Integers and Number Types | 整数与数字类型

Integer: An integer is any positive or negative whole number, including zero. Examples: -3, 0, 7. Memory tip: think of it as in-tegral – whole and unbroken, just like whole numbers.

整数：整数包括所有正整数、负整数和零。例：-3,0,7。记忆：将它联想为’完整无缺’，就像整数本身那样，没有分数部分。

Prime number: A prime number has exactly two distinct factors: 1 and itself. 2, 3, 5, 7, 11 are primes. Memory: prime means first-rate; a prime number is only built from the first things – 1 and itself.

质数（素数）：质数只有两个不同的因数：1和它本身。2,3,5,7,11是质数。记忆：prime有’首要的’之意，质数只由最基本的两个因数构成。

Composite number: A composite number has more than two factors. For example, 12 has factors 1,2,3,4,6,12. Think of a composite material made of many parts.

合数：合数有两个以上的因数。如12的因数有1,2,3,4,6,12。想象成’组合材料’，由多个部件组成。

Square number: The product of an integer multiplied by itself, e.g. 4² = 16. Visualise a 4×4 dot grid to make a square. Tip: square numbers like 9, 16, 25 always form a geometric square.

平方数：一个整数乘以它本身的结果，如4²=16。想象一个4×4的点阵正方形。记忆：9,16,25等平方数总能在几何上排成正方形。

Cube number: The product of an integer multiplied by itself twice, e.g. 2³ = 8. Think of a Rubik’s cube made of small unit cubes. This helps you remember the third power.

立方数：一个整数自乘两次的结果，如2³=8。想象魔方由小立方体组成，帮你记住三次幂。

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2. Powers, Roots and Standard Form | 幂、根与标准形式

Index (exponent): The small number written above and to the right of a base number showing how many times the base is multiplied by itself. In 5³, the index is 3. Memory: index like pointing a finger upward – it points to repeated multiplication.

指数（幂）：写在底数右上角的小数字，表示底数自乘的次数。5³中指数是3。记忆：index像一根向上指的手指，指示重复相乘。

Square root (√): The number that, when multiplied by itself, gives the original number. √25 = 5 because 5×5=25. Visualise a square area: if area is 25, side is √25 = 5.

平方根 (√)：与自身相乘得到原数的数。√25=5，因为5×5=25。想象正方形面积：若面积是25，边长就是√25=5。

Cube root (³√): The number that when cubed gives the original number. ³√8 = 2. Think of reversing the cube: from a 2×2×2 cube you get the root 2.

立方根 (³√)：三次方后得到原数的数。³√8=2。想象逆转立方体：从一个2×2×2立方体得到根2。

Standard form (scientific notation): A way of writing very large or very small numbers using powers of 10. E.g., 3.2 × 10⁴ = 32 000. Memory: the exponent counts how many places the decimal point moves.

标准形式（科学记数法）：用10的幂表示极大或极小数的方法。如3.2 × 10⁴ = 32 000。记忆：指数就是小数点移动的位数。

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3. Fractions, Decimals and Percentages | 分数、小数与百分数

Numerator and denominator: In a fraction, the top number is the numerator, the bottom is the denominator. 3/4: 3 is numerator. Tip: the denominator is down – it tells you how many equal parts the whole is divided into.

分子与分母：分数中，上面的数是分子，下面是分母。3/4中3是分子。记忆：分母在下，告诉你整体被分成了多少等份。

Equivalent fractions: Fractions that represent the same value, e.g. 1/2 = 2/4 = 4/8. Think of cutting a pizza differently but getting the same amount.

等值分数：表示相同值的分数，如1/2=2/4=4/8。想象切披萨方式不同，但得到的量一样。

Recurring decimal: A decimal that repeats forever, like 0.333… = 1/3. A dot over the repeating digit marks it. Memory: the number recurs or keeps coming back.

循环小数：无限重复的小数，如0.333…=1/3。在循环数字上方加点表示。记忆：数字 recur（再发生），不断回来。

Percentage increase and decrease: Change expressed as a per cent of the original amount. Use the formula: % change = (difference ÷ original) × 100. Link it with sales discounts in real life.

百分数增减：相对于原量用百分比表示的变动。公式：%变化=(差值÷原值)×100。联系生活中的打折降价来记忆。

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4. Algebraic Expressions | 代数表达式

Variable: A symbol, usually a letter, that represents an unknown number. In 2x + 5, x is the variable. Think: variable means changeable – its value can vary.

变量：通常用字母表示未知数的符号。在2x+5中，x是变量。记忆：variable意为可变的，其值可以变化。

Coefficient: The number multiplying a variable. In 3y, 3 is the coefficient. Memory: co- means together, efficient – the number that works with the variable.

系数：乘以变量的数。3y中3是系数。记忆：co- 意为’共同’，联合作用 – 与变量一起起作用的数字。

Constant: A fixed value that does not change. In 4x + 7, 7 is the constant. Picture a constant friend who never changes.

常数：固定不变的数值。在4x+7中，7是常数。想象一个始终不变的朋友。

Like terms: Terms that contain the same variable raised to the same power. 2x and -5x are like terms; 3x² and 4x are not. Memory: they are ‘like’ each other because the variable part is identical.

同类项：含有相同变量且指数相同的项。2x和-5x是同类项；3x²和4x不是。记忆：它们彼此相’像’，因为变量部分一样。

Expression vs equation: An expression is a combination of terms without an equals sign (e.g. 3x+2). An equation has an equals sign showing two expressions are equal (e.g. 3x+2=11). Think: expression expresses a value; equation equates two sides.

表达式与方程：表达式是项的组合，没有等号（如3x+2）。方程带有等号，表示两个表达式相等（如3x+2=11）。记忆：表达式表达一个值；方程让两边相等。

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5. Equations and Inequalities | 方程与不等式

Solution (root): The value of the variable that makes an equation true. For x+3=7, the solution is 4. Visualise putting the right key into a lock.

解（根）：使方程成立的变量值。x+3=7的解是4。想象用正确的钥匙打开锁。

Inverse operation: The opposite mathematical process. Addition and subtraction are inverses; so are multiplication and division. To solve an equation, use inverse operations like retracing steps.

逆运算：相反的数学运算。加和减互为逆运算；乘和除也是。解方程时使用逆运算，像原路返回。

Inequality symbols: < (less than), > (greater than), ≤ (less than or equal to), ≥ (greater than or equal to). Think of the symbol as a hungry crocodile always wanting to eat the bigger number.

不等号：< (小于), > (大于), ≤ (小于等于), ≥ (大于等于)。想象一条饥饿的鳄鱼总是张嘴朝向较大的数。

Linear inequality: An inequality that can be written as ax + b < c, etc. The solution is a range of values. Memory: linear means straight line – the solutions lie on one side of a boundary.

线性不等式：形如ax+b

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6. Sequences | 序列

Sequence: An ordered list of numbers following a rule. 2,4,6,8,… is a sequence. Memory: se-quence sounds like ‘see quence’ meaning see the order.

序列：按规则排列的一列数。如2,4,6,8,…。记忆：sequence（序列）强调有序性。

Term: Each number in a sequence. In 3,5,7,9, the first term is 3. Think of terms as step stones in a path.

项：序列中的每个数。在3,5,7,9中，第一项是3。想象成路径上的一块块垫脚石。

Nth term: A formula that allows you to find any term in a sequence. For 2,4,6,8,…, nth term = 2n. The n stands for the position number. It’s a shortcut for the whole sequence.

第n项：能求出序列中任意一项的公式。对2,4,6,8,…，第n项=2n。其中n代表位置序号。这是全序列的快速通道。

Arithmetic sequence: A sequence with a common difference between consecutive terms. E.g., 5,8,11,14 – difference is 3. Think ‘add the difference each time’.

等差数列：相邻项之差为常数的序列。如5,8,11,14，公差为3。记忆：每次加上固定的差。

Geometric sequence: A sequence where each term is multiplied by a common ratio to

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