📚 KS3 Mathematics: Essential Maths Book 8S Compressed – Question Type Analysis | KS3 数学:Essential Maths Book 8S 压缩版题型解析
Welcome to this in-depth question type analysis of the Essential Maths Book 8S (Compressed edition), a key resource for KS3 students aiming to build solid mathematical foundations. In this article, we break down the most common and challenging question types found in the book, providing step-by-step explanations and bilingual insights to help you master each concept. Whether you are preparing for school assessments or reinforcing your skills, this guide will serve as your comprehensive companion.
欢迎来到本篇针对《Essential Maths Book 8S(压缩版)》的深度题型解析,该书是KS3学生夯实数学基础的重要资源。本文我们将拆解书中出现最频繁、最具挑战性的题型,提供逐步解析与双语解读,助你掌握每一个概念。无论你是在备考学校测验,还是巩固技能,本指南都将成为你的全方位伴侣。
1. Number Operations and BIDMAS | 整数运算与BIDMAS
Question Type 1: Evaluating expressions with brackets, indices and mixed operations. Example: Work out 15 – 3 × (4² – 6). Follow BIDMAS: Brackets first: 4² = 16, then 16 – 6 = 10. Next Multiplication: 3 × 10 = 30. Finally Subtraction: 15 – 30 = –15.
题型1:计算含有括号、指数和混合运算的表达式。示例:计算 15 – 3 × (4² – 6)。遵循 BIDMAS 规则:先算括号内部:4² = 16,然后 16 – 6 = 10。接着乘法:3 × 10 = 30。最后减法:15 – 30 = –15。
Question Type 2: Real-life application involving multi-step calculations. A family buys 3 adult cinema tickets at £8.50 each and 2 child tickets at £5.20 each. They pay with a £50 note. Calculate the total cost and the change. Total cost = (3 × 8.50) + (2 × 5.20) = 25.50 + 10.40 = £35.90. Change = 50.00 – 35.90 = £14.10. Always remember to write the final answer with the correct unit.
题型2:涉及多步运算的实际应用题。某家庭购买3张成人电影票,每张8.50英镑,2张儿童票,每张5.20英镑。他们用一张50英镑的纸币支付。计算总花费和找回的零钱。总花费 = (3 × 8.50) + (2 × 5.20) = 25.50 + 10.40 = 35.90英镑。找回 = 50.00 – 35.90 = 14.10英镑。务必记得用正确的单位写出最终答案。
2. Fractions, Decimals and Percentages – Conversions and Calculations | 分数、小数与百分比——转换与计算
Question Type 3: Ordering a mix of fractions, decimals and percentages. Put these in ascending order: 0.35, 2/5, 28%, 0.3, 1/4. A reliable method is to convert all values to decimals or percentages. As decimals: 0.35, 2/5 = 0.4, 28% = 0.28, 0.3, 1/4 = 0.25. Ascending order: 1/4 (0.25), 28% (0.28), 0.3, 0.35, 2/5 (0.4).
题型3:将分数、小数和百分数混合排序。按升序排列:0.35,2/5,28%,0.3,1/4。可靠的方法是将所有值转换为小数或百分数。转换为小数:0.35,2/5 = 0.4,28% = 0.28,0.3,1/4 = 0.25。升序排列为:1/4 (0.25),28% (0.28),0.3,0.35,2/5 (0.4)。
Question Type 4: Adding and subtracting mixed numbers. Example: 2 ½ + 1 ⅓. Convert to improper fractions: 2 ½ = 5/2, 1 ⅓ = 4/3. Find a common denominator: LCM of 2 and 3 is 6. 5/2 = 15/6, 4/3 = 8/6. Add: 15/6 + 8/6 = 23/6 = 3 ⅚.
题型4:带分数的加减法。示例:2 ½ + 1 ⅓。转化为假分数:2 ½ = 5/2,1 ⅓ = 4/3。找到公分母:2和3的最小公倍数为6。5/2 = 15/6,4/3 = 8/6。相加:15/6 + 8/6 = 23/6 = 3 ⅚。
Question Type 5: Percentage increase and decrease problems. A coat originally costs £120. In a sale, it is reduced by 25%. Find the sale price. 25% of £120 = 0.25 × 120 = £30. Sale price = 120 – 30 = £90. Alternatively, a 25% reduction means you pay 75%, so 0.75 × 120 = £90.
题型5:百分比增减问题。一件外套原价120英镑。商家降价25%出售,求售价。120的25%为 0.25 × 120 = 30英镑。售价 = 120 – 30 = 90英镑。亦可理解为降价25%后支付原价的75%,即 0.75 × 120 = 90英镑。
3. Ratio and Proportion – Sharing and Scale | 比与比例——分配与比例尺
Question Type 6: Sharing a quantity in a given ratio. Share £84 between Anna and Ben in the ratio 3:4. Total number of parts = 3 + 4 = 7. Value of one part = £84 ÷ 7 = £12. Anna gets 3 × 12 = £36, Ben gets 4 × 12 = £48. Always check that the amounts sum to the original total.
题型6:按给定比例分配数量。将84英镑按3:4分配给Anna和Ben。总份数 = 3 + 4 = 7。每份的价值 = 84 ÷ 7 = 12英镑。Anna获得 3 × 12 = 36英镑,Ben获得 4 × 12 = 48英镑。务必检查分配的总和等于原始总量。
Question Type 7: Using scale factors in recipes and maps. A recipe for 6 people uses 450g of flour. How much flour is needed for 15 people? The scale factor = 15/6 = 5/2 = 2.5. Amount of flour = 450g × 2.5 = 1125g (or 1.125 kg). On a map with scale 1:25000, a distance of 4 cm represents 4 × 25000 cm = 100000 cm = 1 km.
题型7:在食谱和地图中使用比例因子。一份为6人份的食谱用450克面粉。15人份需要多少面粉?比例因子 = 15/6 = 5/2 = 2.5。面粉用量 = 450克 × 2.5 = 1125克(或1.125千克)。在比例尺为1:25000的地图上,4厘米的距离表示 4 × 25000 厘米 = 100000 厘米 = 1 千米。
4. Algebraic Expressions – Simplifying and Substituting | 代数表达式——化简与代入
Question Type 8: Collecting like terms. Simplify 5x + 3y – 2x + 7y. Combine x terms: 5x – 2x = 3x. Combine y terms: 3y + 7y = 10y. Final simplified expression: 3x + 10y. Be careful with signs; if there is a minus before a term, take it with the sign.
题型8:合并同类项。化简 5x + 3y – 2x + 7y。合并含x的项:5x – 2x = 3x。合并含y的项:3y + 7y = 10y。化简后的表达式:3x + 10y。注意符号,如果项前面有减号,要连同符号一起处理。
Question Type 9: Expanding single brackets. Expand 4(2a – 3b + 5). Multiply each term inside the bracket by 4: 4 × 2a = 8a, 4 × (–3b) = –12b, 4 × 5 = 20. Result: 8a – 12b + 20.
题型9:单项式乘多项式(展开单项括号)。展开 4(2a – 3b + 5)。将括号内的每一项都乘以4:4 × 2a = 8a,4 × (–3b) = –12b,4 × 5 = 20。结果:8a – 12b + 20。
Question Type 10: Substituting values into expressions. If a = 3, b = –2 and c = 5, evaluate 2a² – bc. Substitute: 2 × (3)² – (–2) × 5 = 2 × 9 – (–10) = 18 + 10 = 28. Remember that a negative number squared becomes positive, and subtracting a negative is adding.
题型10:代入数值求表达式的值。已知 a = 3,b = –2,c = 5,求 2a² – bc 的值。代入:2 × (3)² – (–2) × 5 = 2 × 9 – (–10) = 18 + 10 = 28。牢记负数平方得正,减去一个负数等于加上它的相反数。
5. Solving Linear Equations – One-step to Multi-step | 解一元一次方程——从一步到多步
Question Type 11: One-step equations using inverse operations. Solve x + 9 = 15. Subtract 9 from both sides: x = 6. Solve 7y = 42. Divide both sides by 7: y = 6. The key is to perform the same operation on both sides to isolate the variable.
题型11:运用逆运算解一步方程。解方程 x + 9 = 15。两边同时减去9:x = 6。解方程 7y = 42。两边同时除以7:y = 6。关键是对等式两边执行相同的运算,以单独分离出未知数。
Question Type 12: Equations with unknowns on both sides. Solve 2x + 5 = x + 11. Subtract x from both sides: x + 5 = 11. Then subtract 5: x = 6. For 3x – 4 = 2x + 1, subtract 2x: x – 4 = 1, then add 4: x = 5. Always aim to collect x‑terms on one side and constants on the other.
题型12:两边均含未知数的方程。解方程 2x + 5 = x + 11。两边同时减去 x:x + 5 = 11。再减去5:x = 6。对于 3x – 4 = 2x + 1,减去2x得 x – 4 = 1,然后加4得 x = 5。始终要把含未知数的项集中到一边,常数项集中到另一边。
Question Type 13: Equations involving brackets and fractions. Solve 3(2x – 1) = 21. Expand first: 6x – 3 = 21. Add 3: 6x = 24, so x = 4. Solve (x/4) + 2 = 5. Subtract 2: x/4 = 3. Multiply by 4: x = 12. With fractions, treat the fraction bar as division and multiply to clear it.
题型13:含有括号和分数的方程。解 3(2x – 1) = 21。先展开:6x – 3 = 21。加3:6x = 24,故 x = 4。解方程 (x/4) + 2 = 5。减去2:x/4 = 3。两边乘以4:x = 12。对于分数,将分数线视为除法,并乘以分母以消去分数。
6. Sequences – Finding the nth Term | 数列——求第n项公式
Question Type 14: Generating terms from a rule. The nth term of a sequence is given by 4n – 5. Write down the first three terms. For n = 1: 4(1) – 5 = –1. n = 2: 8 – 5 = 3. n = 3: 12 – 5 = 7. So the sequence begins –1, 3, 7, …
题型14:根据通项公式生成数列的项。某数列的第n项公式为 4n – 5。写出该数列的前三项。n = 1:4(1) – 5 = –1。n = 2:8 – 5 = 3。n = 3:12 – 5 = 7。因此数列前几项为 –1,3,7……
Question Type 15: Finding the nth term of a linear sequence. Find the nth term of the sequence 5, 9, 13, 17, 21… The difference between terms is +4. So the coefficient of n is 4. To find the zero term (term before the first), subtract 4 from 5: 5 – 4 = 1. So the nth term is 4n + 1. Test for n=3: 4×3+1=13, correct.
题型15:求线性数列的第n项公式。求数列 5,9,13,17,21…… 的第n项公式。相邻项的差为 +4,故 n 的系数是 4。为找到第零项(第一项前面的项),从第一项 5 中减去 4,得 1。因此第n项公式为 4n + 1。检验 n=3:4×3+1=13,正确。
Question Type 16: Using the nth term to find if a number is in the sequence. Is 97 in the sequence 8, 13, 18, 23…? The common difference is 5, and the first term is 8, so nth term = 5n + 3 (since 8–5=3). Set 5n + 3 = 97 → 5n = 94 → n = 18.8. n is not a whole number, so 97 is not in the sequence.
题型16:用第n项公式判断一个数是否属于数列。97是否属于数列 8,13,18,23……?公差为5,首项为8,因此第n项 = 5n + 3(因为8–5=3)。令 5n + 3 = 97,得 5n = 94,n = 18.8。n 不是整数,因此97不属于该数列。
7. Angles and Parallel Lines – Reasoning | 角度与平行线——推理
Question Type 17: Calculating angles on a straight line and around a point. Find the missing angle a in the diagram where two angles on a straight line are 43° and a. Since angles on a straight line sum to 180°, a = 180° – 43° = 137°. For a full turn, if three angles are 120°, 90° and b, then b = 360° – (120°+90°) = 150°.
题型17:计算直线上的角和绕一点的角度。如图所示,一条直线上有两个角 43° 和 a,求缺失的角 a。直线上两角之和为180°,故 a = 180° – 43° = 137°。对于周角,若三个角分别为 120°、90° 和 b,则 b = 360° – (120°+90°) = 150°。
Question Type 18: Angles in parallel lines with a transversal. In a diagram with parallel lines and a transversal, a corresponding angle to 55° is also 55°. Alternate angles are equal, and co‑interior (allied) angles sum to 180°. If an alternate angle is 72°, the other is 72°. If a co‑interior angle is 108°, its partner is 180° – 108° = 72°. Practice identifying the angle pairs.
题型18:平行线与截线形成的角。在平行线与截线的图中,与55°对应的同位角也是55°。内错角相等,同旁内角之和为180°。若一个内错角为72°,另一个也为72°。若一个同旁内角为108°,则与其共轭的角为 180° – 108° = 72°。多练习识别各类角对。
Question Type 19: Angles in triangles and quadrilaterals. In a triangle, given angles of 45° and 70°, the third angle = 180° – (45°+70°) = 65°. For a quadrilateral, the sum of interior angles is 360°. If three angles are 95°, 80° and 110°, the fourth is 360° – (95+80+110) = 75°.
题型19:三角形和四边形的内角。在三角形中,已知两个角分别为45°和70°,则第三个角 = 180° – (45°+70°) = 65°。在四边形中,内角和为360°。若三个角分别为95°、80°和110°,则第四个角为 360° – (95+80+110) = 75°。
8. Area and Perimeter – Composite Shapes | 面积与周长——组合图形
Question Type 20: Perimeter of rectilinear shapes. Find the perimeter of an L‑shaped figure composed of two rectangles. Break the shape into known sides, carefully deduce missing side lengths using the fact that opposite sides of a rectangle are equal. Sum all outer side lengths to obtain the perimeter. Always include units (e.g., cm, m).
题型20:直线围成图形的周长。求一个由两个矩形组成的L形图形的周长。将图形拆分成已知边长,利用矩形对边相等的性质仔细推导出缺失的边长。将所有外部边长相加即得周长。务必标注单位(如厘米、米)。
Question Type 21: Area of triangles, parallelograms and trapeziums. Area of a triangle = ½ × base × vertical height. For a triangle with base 8 cm and height 5 cm: area = ½ × 8 × 5 = 20 cm². Area of a parallelogram = base × vertical height. Area of a trapezium = ½ × (a + b) × h, where a and b are parallel sides. Use the perpendicular height, not the slant height.
题型21:三角形、平行四边形和梯形的面积。三角形面积 = ½ × 底 × 高。底8厘米、高5厘米的三角形面积为 ½ × 8 × 5 = 20 平方厘米。平行四边形面积 = 底 × 高。梯形面积 = ½ × (上底 + 下底) × 高,其中上底和下底为平行边。务必使用垂直高度,而非斜高。
Question Type 22: Area of compound shapes. Split a compound shape into rectangles, triangles and semicircles where possible. Calculate each area separately and add (or subtract for holes). Example: an arrowhead made of a rectangle and a triangle: area = rectangle area + triangle area.
题型22:组合图形的面积。尽可能将组合图形分割为矩形、三角形和半圆形。分别计算各部分的面积,然后相加(若有镂空则减去)。例如,由一个矩形和一个三角形组成的箭头图形:总面积 = 矩形面积 + 三角形面积。
9. Volume and Surface Area – Cuboids and Prisms | 体积与表面积——长方体和棱柱
Question Type 23: Volume of a cuboid. Volume = length × width × height. A cuboid with dimensions 4 cm by 3 cm by 10 cm has volume = 4 × 3 × 10 = 120 cm³. Ensure the units match and the answer is in cubic units.
题型23:长方体的体积。体积 = 长 × 宽 × 高。一个长4厘米、宽3厘米、高10厘米的长方体体积为 4 × 3 × 10 = 120 立方厘米。确保单位一致,答案以立方单位表示。
Question Type 24: Volume of prisms (e.g., triangular prism). Volume of any prism = area of cross‑section × length. For a triangular prism with a right‑angled triangle cross‑section (base 5 cm, height 6 cm) and length 12 cm: cross‑sectional area = ½ × 5 × 6 = 15 cm². Volume = 15 × 12 = 180 cm³.
题型24:棱柱的体积(如三棱柱)。任何棱柱的体积 = 横截面积 × 长度。对于一个横截面为直角三角形(底5厘米、高6厘米)、长度12厘米的三棱柱:横截面积 = ½ × 5 × 6 = 15 平方厘米。体积 = 15 × 12 = 180 立方厘米。
Question Type 25: Surface area of a cuboid. Surface area = 2(lw + wh + lh). For a cuboid 5 cm × 3 cm × 4 cm: lw = 15, wh = 12, lh = 20. Sum = 47. Surface area = 2 × 47 = 94 cm². It helps to sketch a net to visualise all six faces.
题型25:长方体的表面积。表面积 = 2(长×宽 + 宽×高 + 长×高)。对于一个5厘米 × 3厘米 × 4厘米的长方体:长×宽=15,宽×高=12,长×高=20。总和 = 47。表面积 = 2 × 47 = 94 平方厘米。画出展开图有助于可视化所有六个面。
10. Statistics and Probability – Averages and Simple Probability | 统计与概率——平均数与简单概率
Question Type 26: Mean, median, mode and range. For the data set: 4, 8, 6, 5, 8, 3. Mode is 8 (most frequent). Range = 8 – 3 = 5. Mean = (4+8+6+5+8+3)/6 = 34/6 ≈ 5.67. For median, order: 3,
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