Cambridge KS3 Maths: Practice Page 154 Set 2 | 剑桥KS3数学：第154页练习2

📚 Cambridge KS3 Maths: Practice Page 154 Set 2 | 剑桥KS3数学：第154页练习2

Welcome to this focused revision guide for a Cambridge KS3 Mathematics practice set. The questions on page 154, set 2, combine core skills you will meet in the Lower Secondary Checkpoint: number operations, fractions, decimals, percentages, introductory algebra and angle facts. Work through each section slowly, and always show your method.

欢迎使用这份针对剑桥 KS3 数学练习的复习指南。第154页第2组题目综合了初中 Checkpoint 阶段的核心技能：数的运算、分数、小数、百分数、代数初步和角的基本知识。请仔细完成每一节，并始终写出解题过程。

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1. Reading the Question | 审题

Before you calculate, underline the command word and the unit you need. For example, work out, simplify, find the value of x or give your answer as a fraction in its lowest terms tells you how to present the final answer.

在动笔计算之前，先圈出题目中的指令词和单位。例如计算、化简、求 x 的值，或者答案要求用最简分数表示，这些都会告诉你最终答案应该如何呈现。

Many marks are lost because students skip the units or leave a fraction that can be cancelled. If the question asks for centimetres, write cm; if it asks for degrees, write the ° symbol.

很多失分是因为学生漏写单位，或者留下了还能约分的分数。如果题目要求用厘米，就写 cm；如果要求用度，就写 °。

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2. Number Operations | 数的运算

Use the correct order of operations: brackets first, then indices, then multiplication and division from left to right, and finally addition and subtraction from left to right. The sequence BIDMAS or BODMAS helps you remember this order.

使用正确的运算顺序：先算括号，再算指数，然后从左到右进行乘除，最后从左到右进行加减。BIDMAS 或 BODMAS 口诀可以帮助你记住这一顺序。

2 + 3 × 4 = 2 + 12 = 14

With negative numbers, a minus sign changes direction on the number line. For addition and subtraction, two signs next to each other can be replaced: + (−) becomes − and − (−) becomes +.

处理负数时，负号会在数轴上改变方向。加减法中，相邻的两个符号可以合并：+（−）变成 −，−（−）变成 +。

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3. Factors and Multiples | 因数与倍数

A factor divides exactly into a number. The highest common factor (HCF) is the largest number that divides two or more numbers exactly. A multiple is the product of the number and any integer; the lowest common multiple (LCM) is the smallest multiple shared by two or more numbers.

因数可以整除一个数。最大公因数（HCF）是能同时整除两个或多个数的最大整数。倍数是该数与任意整数相乘的结果；最小公倍数（LCM）是两个或多个数共有的最小倍数。

For 12 and 18, the factors of 12 are 1, 2, 3, 4, 6, 12 and the factors of 18 are 1, 2, 3, 6, 9, 18. The HCF is 6, and the LCM is 36.

对于 12 和 18，12 的因数是 1、2、3、4、6、12，18 的因数是 1、2、3、6、9、18。它们的 HCF 是 6，LCM 是 36。

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4. Fractions | 分数

To add or subtract fractions, make the denominators the same. For 2/3 + 1/4, the common denominator is 12, so 2/3 = 8/12 and 1/4 = 3/12. The sum is 11/12.

分数加减前，先把分母通分。例如 2/3 + 1/4，公分母是 12，于是 2/3 = 8/12、1/4 = 3/12，和为 11/12。

2/3 + 1/4 = 8/12 + 3/12 = 11/12

To multiply fractions, multiply the numerators and multiply the denominators. To divide by a fraction, flip the second fraction and then multiply. Always simplify your answer to its lowest terms.

分数相乘，分子乘分子，分母乘分母。除以一个分数时，将第二个分数倒过来再相乘。最后一定要把答案化为最简分数。

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5. Decimals and Percentages | 小数与百分数

A percentage means ‘out of 100’. To convert a percentage to a decimal, divide by 100; for example, 65% = 0.65. To convert a decimal to a percentage, multiply by 100.

百分数表示每一百份中的多少份。把百分数化为小数，除以 100 即可；例如 65% = 0.65。把小数化为百分数，则乘以 100。

To find a percentage of an amount, multiply the amount by the percentage as a decimal. Thus 15% of £80 is 0.15 × 80 = £12.

求一个数量的百分数，将数量乘以百分数对应的小数。因此 80 英镑的 15% 是 0.15 × 80 = 12 英镑。

Fraction 1/4	Decimal 0.25	Percentage 25%
Fraction 3/5	Decimal 0.6	Percentage 60%
Fraction 7/10	Decimal 0.7	Percentage 70%

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6. Algebraic Simplification | 代数式的化简

Like terms contain the same letter part. You can combine 3x and 5x to get 8x, but you cannot combine 3x and 3x² because the powers are different.

同类项含有相同的字母部分。你可以把 3x 和 5x 合并为 8x，但不能把 3x 和 3x² 合并，因为次数不同。

3x + 5x − 2x = 6x

When you multiply terms, multiply the numbers and add the indices of the same letter. For example, 2x × 3x² = 6x³.

单项式相乘时，数字相乘，相同字母的指数相加。例如 2x × 3x² = 6x³。

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7. Solving Linear Equations | 解一元一次方程

To solve an equation, do the same operation to both sides. Undo the constants first, then divide by the coefficient of x. For 2x + 3 = 11, subtract 3 from both sides to get 2x = 8, then divide by 2 to get x = 4.

解方程时，两边同时进行相同的运算。先消去常数项，再除以 x 的系数。对于 2x +

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