📚 Year 8 OCR Further Mathematics: Unit Test Mock Paper Walkthrough | Year 8 OCR 进阶数学:单元测试模拟卷解析
This walkthrough takes you through a full mock paper designed to mirror the style of a Year 8 OCR Further Mathematics unit test. Each section presents a typical exam-style question, followed by a clear, step-by-step solution. The topics covered include algebra, geometry, probability, ratio and statistics — all key areas in the OCR Further Mathematics programme for Year 8.
本文详细解析一套模拟单元测试卷,题目风格与 Year 8 OCR 进阶数学考试一致。每个小节都会展示一道典型考题,并给出清晰的逐步解答。覆盖的主题包括代数、几何、概率、比例和统计,均为 Year 8 OCR 进阶数学课程的核心内容。
1. Simplifying Algebraic Expressions | 简化代数表达式
Question: Simplify 5a + 3b − 2a + 7b − 4a.
题目:化简 5a + 3b − 2a + 7b − 4a。
Start by identifying like terms. Terms containing ‘a’ are 5a, −2a and −4a. Terms containing ‘b’ are 3b and 7b.
首先识别同类项。含有 a 的项为 5a、−2a 和 −4a。含有 b 的项为 3b 和 7b。
Now group and combine the coefficients: (5 − 2 − 4)a gives −1a, which is written as −a. For the b terms, (3 + 7)b simplifies to 10b.
接着分组并合并系数:(5 − 2 − 4)a 得到 −1a,写作 −a。对于 b 项,(3 + 7)b 化简为 10b。
The final simplified expression is −a + 10b. It is conventional to write terms with a positive coefficient first if possible, but both forms are acceptable.
最终化简结果为 −a + 10b。习惯上尽可能将正系数项写在前面,但两种形式均可接受。
2. Solving Linear Equations | 解一元一次方程
Question: Solve 4(x − 3) + 2x = 5x + 8.
题目:解方程 4(x − 3) + 2x = 5x + 8。
First expand the bracket: 4 × x = 4x and 4 × (−3) = −12, so the left-hand side becomes 4x − 12 + 2x.
首先展开括号:4 × x = 4x,4 × (−3) = −12,因此左边变为 4x − 12 + 2x。
Simplify the left by combining like terms: 4x + 2x gives 6x. The equation is now 6x − 12 = 5x + 8.
合并左边的同类项:4x + 2x 得到 6x。方程现在为 6x − 12 = 5x + 8。
Subtract 5x from both sides to collect x terms together: 6x − 5x − 12 = 8, so x − 12 = 8.
两边同时减去 5x 将含 x 的项移到一边:6x − 5x − 12 = 8,即 x − 12 = 8。
Finally add 12 to both sides: x = 20. Substitute back to check: 4(20−3)+40 = 4×17+40 = 68+40=108, and 5×20+8=100+8=108.
最后两边同时加 12:x = 20。代入检验:4(20−3)+40=4×17+40=68+40=108,5×20+8=100+8=108,结果正确。
3. Inequalities on a Number Line | 数轴上的不等式
Question: Represent the inequality −2 < x ≤ 3 on a number line and list the integer values that satisfy it.
题目:在数轴上表示不等式 −2 < x ≤ 3,并列出所有满足条件的整数值。
An open circle is placed at −2 to show that x is strictly greater than −2 (not equal). A closed circle is placed at 3 to show that x can equal 3. Shade the region between them.
在 −2 处画空心圆,表示 x 严格大于 −2(不能等于)。在 3 处画实心圆,表示 x 可以等于 3。将两点之间的区域涂上阴影。
The integers that satisfy −2 < x ≤ 3 are those whole numbers strictly greater than −2 and up to 3 inclusive. So x can be −1, 0, 1, 2, 3.
满足 −2 < x ≤ 3 的整数是那些严格大于 −2 且不超过 3 的整数。因此 x 可以是 −1、0、1、2、3。
Note that −2 itself is not included because of the strict inequality sign. Students often forget to exclude the boundary when drawing open circles.
注意 −2 本身并不包含在内,因为使用了严格不等号。学生在画空心圆时经常忘记排除边界。
4. nth Term of a Linear Sequence | 线性序列的第 n 项
Question: The first four terms of a sequence are 7, 11, 15, 19. Find the nth term and use it to calculate the 50th term.
题目:某序列的前四项为 7、11、15、19。求第 n 项公式,并计算第 50 项。
Determine the common difference by subtracting consecutive terms: 11 − 7 = 4, 15 − 11 = 4. This tells us the coefficient of n is 4, so the nth term is of the form 4n + c.
通过相邻项相减求公差:11 − 7 = 4,15 − 11 = 4。这说明 n 的系数为 4,因此第 n 项的形式为 4n + c。
To find c, use the first term (n = 1). If 4(1) + c = 7, then 4 + c = 7, so c = 3. Hence the nth term is 4n + 3.
为求 c,代入第一项(n = 1)。若 4(1) + c = 7,则 4 + c = 7,得 c = 3。因此第 n 项公式为 4n + 3。
For the 50th term, substitute n = 50: 4(50) + 3 = 200 + 3 = 203. Always verify with an early term: n=2 gives 4×2+3=11, which matches.
第 50 项需代入 n = 50:4(50) + 3 = 200 + 3 = 203。务必用早期项验证:n=2 得 4×2+3=11,与序列一致。
5. Angles in Polygons | 多边形内角
Question: A regular polygon has interior angle 156°. How many sides does it have?
题目:一个正多边形的每个内角为 156°。它有多少条边?
Use the relationship between interior and exterior angles. The sum of an interior and its corresponding exterior angle is 180°, so exterior angle = 180° − 156° = 24°.
利用内角和外角的关系。任一个内角与其相邻外角之和为 180°,因此外角 = 180° − 156° = 24°。
For any regular polygon, the sum of all exterior angles is 360°. If each exterior angle is 24°, the number of sides n satisfies 24n = 360. Divide both sides by 24: n = 360 ÷ 24 = 15.
任意正多边形的外角和恒为 360°。若每个外角为 24°,则边数 n 满足 24n = 360。两边除以 24:n = 360 ÷ 24 = 15。
Thus the polygon has 15 sides — a pentadecagon. This method avoids memorising the interior angle formula and reduces arithmetic errors.
因此该多边形有 15 条边,即十五边形。这种方法无需死记内角和公式,并能减少计算错误。
6. Probability of Combined Events | 组合事件概率
Question: A fair six-sided die is rolled and a fair coin is flipped. What is the probability of rolling a number greater than 4 and getting a head?
题目:同时掷一枚公平的六面骰子和抛一枚公平的硬币。求掷出大于 4 的点数且硬币正面朝上的概率。
The two events are independent. The probability of rolling a number greater than 4 (i.e., 5 or 6) is 2 out of 6, which simplifies to 1/3.
两个事件相互独立。掷出大于 4 的点数(即 5 或 6)的概率为 2/6,化简为 1/3。
The probability of getting a head is 1/2. Multiply the separate probabilities: P(greater than 4 AND head) = (1/3) × (1/2) = 1/6.
得到正面的概率为 1/2。将两个概率相乘:P(大于 4 且正面) = (1/3) × (1/2) = 1/6。
We can verify by listing outcomes: possible favourable pairs are (5,H) and (6,H) out of 12 equally likely outcomes (6 × 2). 2/12 = 1/6, confirming the result.
我们可以通过列举结果来验证:有利组合为 (5,H) 和 (6,H),总共 12 种等可能结果(6×2)。2/12 = 1/6,与结果一致。
7. Ratio and Proportion | 比例与比率
Question: The ratio of boys to girls in a school is 5:4. There are 270 boys. How many students are there in total?
题目:某校男生与女生的数量比为 5:4。已知男生有 270 人,求全校学生总数。
The ratio 5:4 means for every 5 boys there are 4 girls. The number of ‘parts’ for boys is 5, which corresponds to 270. So 1 part = 270 ÷ 5 = 54.
比例 5:4 表示每 5 名男生对应 4 名女生。男生的“份数”为 5,对应 270 人。因此 1 份 = 270 ÷ 5 = 54。
Girls correspond to 4 parts: 4 × 54 = 216. Total students = boys + girls = 270 + 216 = 486.
女生对应 4 份:4 × 54 = 216。总学生数 = 男生 + 女生 = 270 + 216 = 486。
An alternative method is to set up the proportion 5/(5+4) = 270/total, but the unitary method keeps the working clear for Year 8 students.
另一种方法是列出比例式 5/(5+4) = 270/总数,但“每份计算法”对 Year 8 学生而言更加清晰。
8. Simple Interest and Compound Interest | 单利与复利
Question: £800 is invested at 3% per annum simple interest for 4 years. Calculate the total amount after 4 years.
题目:将 800 英镑以年利率 3% 的单利投资 4 年。计算 4 年后的总金额。
Simple interest means the interest earned each year is based only on the original principal. Interest per year = 3% of £800 = 0.03 × 800 = £24.
单利意味着每年的利息仅基于原始本金计算。每年利息 = 800 英镑的 3% = 0.03 × 800 = 24 英镑。
Over 4 years, total interest = 4 × £24 = £96. The total amount after 4 years = principal + interest = £800 + £96 = £896.
4 年内总利息 = 4 × 24 英镑 = 96 英镑。4 年后的总金额 = 本金 + 利息 = 800 英镑 + 96 英镑 = 896 英镑。
If the same principal were invested at compound interest, the calculation would involve multiplying by (1+0.03) each year, yielding a slightly higher amount due to interest on interest.
若以复利计算,则需要每年乘以 (1+0.03),由于“利滚利”效应,最终金额会略高一些。
9. Pythagoras’ Theorem | 勾股定理
Question: A right-angled triangle has legs of length 6 cm and 8 cm. Find the length of the hypotenuse and the area of the triangle.
题目:一个直角三角形的两条直角边分别为 6 cm 和 8 cm。求斜边长和三角形面积。
By Pythagoras, hypotenuse² = 6² + 8². Calculate: 6² = 36, 8² = 64. Sum = 100.
根据勾股定理,斜边² = 6² + 8²。计算:6² = 36,8² = 64。和为 100。
Take the square root: hypotenuse = √100 = 10 cm. The hypotenuse is the longest side, always opposite the right angle.
取平方根:斜边 = √100 = 10 cm。斜边是最长边,总是直角所对的边。
Area of a triangle = ½ × base × height. Here, the legs serve as base and height: area = ½ × 6 × 8 = 24 cm².
三角形面积 = ½ × 底 × 高。直角边可互为底和高:面积 = ½ × 6 × 8 = 24 cm²。
Some students confuse area with perimeter. Keep them separate — perimeter would be 6+8+10 = 24 cm, which coincidentally equals the area number but with different units.
部分学生会将面积与周长混淆。应加以区分——周长为 6+8+10 = 24 cm,数值巧合地等于面积值,但单位不同。
10. Scatter Graphs and Correlation | 散点图与相关性
Question: The table shows test scores in Maths and Science for five students: (12,14), (15,18), (18,22), (21,24), (24,28). Plot a scatter graph and describe the correlation.
题目:下表列出五名学生的数学与科学成绩:(12,14), (15,18), (18,22), (21,24), (24,28)。绘制散点图并描述相关性。
Plot Maths scores on the horizontal axis (x-axis) and Science scores on the vertical axis (y-axis). Each pair becomes a point.
将数学成绩标在横轴(x 轴),科学成绩标在纵轴(y 轴)。每一对对应一个点。
Looking at the trend, as Maths scores increase, Science scores also increase. The points lie roughly along a straight line rising to the right.
观察趋势,随着数学成绩提高,科学成绩也相应提高。这些点大致沿一条向右上升的直线分布。
This indicates a strong positive correlation. ‘Positive’ means the variables move in the same direction; ‘strong’ means the points are closely clustered around an imagined line.
这表明强正相关。“正”意味着两个变量同方向变化;“强”意味着点紧密聚集在一条想象中的直线附近。
We can also draw an approximate line of best fit to make predictions, but be cautious when extrapolating beyond the data range.
我们还可以画一条近似的拟合直线用于预测,但在数据范围外进行外推时需格外谨慎。
11. Solving Linear Inequalities | 解线性不等式
Question: Solve 3(2x − 1) ≤ 5x + 7 and represent the solution on a number line.
题目:解不等式 3(2x − 1) ≤ 5x + 7,并在数轴上表示解集。
Expand the left side: 3×2x = 6x, 3×(−1)=−3, giving 6x − 3 ≤ 5x + 7.
展开左边:3×2x = 6x,3×(−1)=−3,得到 6x − 3 ≤ 5x + 7。
Subtract 5x from both sides: 6x − 5x − 3 ≤ 7, so x − 3 ≤ 7.
两边减去 5x:6x − 5x − 3 ≤ 7,即 x − 3 ≤ 7。
Add 3 to both sides: x ≤ 10. The solution set includes all numbers less than or equal to 10.
两边加 3:x ≤ 10。解集包含所有小于或等于 10 的数。
On a number line, place a closed circle at 10 and shade to the left. A closed circle is used because of the ‘or equal to’ symbol.
在数轴上,在 10 处画实心圆并向左涂阴影。由于含有“或等于”符号,需使用实心圆。
12. Reflections and Key Takeaways | 总结与关键要点
Final tips: Always show clear working — even for simple calculations. Check that negative signs are carried correctly when simplifying expressions. When dealing with inequalities, remember to reverse the inequality sign if multiplying or dividing by a negative number, though that did not arise in this paper.
最后提示:计算步骤务必书写清晰——即使是简单计算也不例外。化简表达式时要确保负号正确无误。处理不等式时,若乘以或除以负数需反转不等号方向,虽然本套试卷未涉及此类情况。
Practise drawing graphs and number lines accurately, as visual representations often earn method marks even if the final answer is slightly off. Use the markscheme-style checking habit: substitute your solution back into the original equation or inequality whenever possible.
平时要练习准确绘制图形和数轴,因为即便最终答案稍有偏差,视觉呈现通常也能获得方法分。养成对照评分标准的检查习惯:尽可能将解代入原方程或原不等式进行验证。
Published by TutorHao | Further Mathematics Revision Series | aleveler.com
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