KS3 Maths: Drawing Graphs Practice | KS3 数学：绘图练习

📚 KS3 Maths: Drawing Graphs Practice | KS3 数学：绘图练习

Drawing graphs is a core skill in the KS3 Cambridge Lower Secondary mathematics curriculum. It connects algebra, coordinates and real-life data, helping students visualise relationships between variables. This article provides guided practice on plotting points, drawing straight lines and curves, and interpreting common graph types.

绘图是 KS3 剑桥初中数学课程的核心技能。它将代数、坐标和实际数据联系起来，帮助学生直观理解变量之间的关系。本文提供关于描点、绘制直线和曲线以及解读常见图像类型的指导练习。

1. Coordinates and the Cartesian Plane | 坐标与笛卡尔平面

The Cartesian plane is formed by two perpendicular number lines: the x-axis (horizontal) and the y-axis (vertical). A point is written as an ordered pair (x, y), where x gives the horizontal distance from the origin and y gives the vertical distance.

笛卡尔平面由两条互相垂直的数轴组成：x 轴（水平）和 y 轴（垂直）。一个点用有序数对 (x, y) 表示，其中 x 表示距原点的水平距离，y 表示垂直距离。

The origin is (0, 0) and it is the point where the axes cross. The plane is divided into four quadrants. In the first quadrant both coordinates are positive; in the second quadrant x is negative and y is positive; in the third quadrant both are negative; in the fourth quadrant x is positive and y is negative.

原点是 (0, 0)，它是两条轴相交的点。平面分为四个象限。第一象限两个坐标均为正；第二象限 x 为负、y 为正；第三象限均为负；第四象限 x 为正、y 为负。

2. Plotting Points from Coordinates | 根据坐标描点

To plot a point such as (3, -2), start at the origin. Move 3 units right because x is positive, then move 2 units down because y is negative. Mark a small cross and label the point if required.

要描出 (3, -2) 这样的点，从原点开始。因为 x 为正，向右移动 3 个单位；因为 y 为负，向下移动 2 个单位。画一个小叉，并在需要时标注该点。

Always check the scale on each axis before plotting, as one square may represent 1, 2, 5 or 10 units. If the scale is not 1:1, do not count squares as single units.

描点前务必检查每个轴上的刻度，因为一个方格可能代表 1、2、5 或 10 个单位。如果刻度不是 1:1，不要把一个方格当作一个单位来数。

3. Tables of Values for Linear Equations | 线性方程的数值表

To draw the graph of a linear equation such as y = 2x + 1, first choose a sensible range of x values, for example from -3 to 3. Substitute each x into the equation to find the matching y value. Record the results in a table.

要绘制 y = 2x + 1 这样的线性方程图像，首先选择一个合适的 x 值范围，例如从 -3 到 3。将每个 x 代入方程，求出对应的 y 值。将结果记录在表格中。