分数条比较

分数条比较
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2016-06-02 21:44
①本范例演示如何使用分数条直观比较两个分数的大小;②涉及的核心数学概念包括分数比较、几何表示、数轴概念;③作图要点——从下方『构造摘要』提炼用到了 GeoGebra 命令 Polygon(多边形)、Sequence(数列)、If(条件判断);④适合小学及以上学段,用于分数教学和可视化理解分数大小关系。

GeoGebra 命令及参数

  1. Polygon((1 - a, 0), (2 - a, 0), 4) → poly1
  2. Polygon((-1 + a, 0), (a, 0), 4) → poly2
  3. Polygon((a - 1 + offset / divisionsL, 0), (a - 1 + offset / divisionsL + shadedL / divisionsL, 0), (a - 1 + offset / divisionsL + shadedL / divisionsL, 1), (a - 1 + offset / divisionsL, 1)) → poly3, f, g, h, i
  4. Sequence(Segment[(1 - a + i / divisionsR, 0), (1 - a + i / divisionsR, 1)], i, 1, divisionsR - 1) → list1
  5. Sequence(Segment[(a - 1 + i / divisionsL, 0), (a - 1 + i / divisionsL, 1)], i, 1, divisionsL - 1) → list2
  6. Polygon((1 - a + offsetR / divisionsR, 0), (1 - a + offsetR / divisionsR + shadedR / divisionsR, 0), (1 - a + offsetR / divisionsR + shadedR / divisionsR, 1), (1 - a + offsetR / divisionsR, 1)) → poly4, j, k, l, m
  7. If(poly3 ≟ poly4, "Same", If[poly3 > poly4, "Bigger", "Smaller"]) → text1
  8. If(poly3 ≟ poly4, "Same", If[poly3 > poly4, "Smaller", "Bigger"]) → text2