数轴上的分数（8岁以上）
Fractions on a number line (age 8+)
在数轴上表示分数：将0到1的区间平均分成b份，找到1/b的位置；再从0开始数出a个1/b的长度，找到a/b的位置。
Represent fractions on a number line: partition the interval 0 to 1 into b equal parts to locate 1/b, then mark off a lengths of 1/b from 0 to locate a/b
学习证据 / Evidence
- 把一条0到1的数轴平均分成4份，并标出1/4
- 解释数轴上每一份的大小是1/b
- 分别在两条数轴上标出1/3和1/6
- 在数轴上从0开始数3个1/4的长度，标出3/4
- 在数轴上标出5/6，并说明过程
- 辨认预先分好份的数轴上一个点所表示的分数
- Partition a 0-to-1 number line into 4 equal parts and mark 1/4
- Explain that each part on the line has size 1/b
- Locate 1/3 and 1/6 on separate number lines
- Locate 3/4 on a number line by counting three 1/4-jumps from 0
- Place 5/6 on a number line and explain the process
- Identify a fraction shown by a point on a pre-partitioned number line
评估问题 / Assessment
如果{{name}}画一条从0到1、平均分成5份的数轴，ta能标出2/5和4/5的位置，并解释自己是怎么算出来的吗？
If {{name}} draws a number line from 0 to 1 split into 5 equal parts, can they label where 2/5 and 4/5 go — and explain how they worked it out?