正比例图像
Proportion Graphs
用双数线（两条在0处对齐的平行数线）和比率表表示正比例关系；理解相等的比在图像上会形成一条过原点的直线。
Represent proportional relationships using double number lines (two parallel number lines aligned at 0) and ratio tables; recognise that equivalent ratios generate straight lines through the origin when graphed
学习证据 / Evidence
- 在坐标网格上描出成正比例的数对，并画出过原点的直线。
- 解释为什么正比例关系的图像总是经过(0,0)。
- 从正比例图像中找出未知值——例如：“如果3千克花费6英镑，5千克需要多少钱？”
- Plot pairs of proportional values on a coordinate grid and draw the straight line through the origin
- Explain why a directly proportional relationship always passes through (0,0)
- Read a proportion graph to find an unknown value — e.g. 'If 3 kg costs £6, how much does 5 kg cost?'
评估问题 / Assessment
如果{{name}}正在比较买不同数量电影票的花费，他们能画出一幅正比例图像——一条过原点的直线——并用它读出任意数量电影票的费用，而不需要每次都重新计算吗？
If {{name}} is comparing the cost of buying different numbers of cinema tickets, can they sketch a proportion graph — a straight line through zero — and use it to read off the cost of any number of tickets without recalculating each time?