分数减法可视化模型
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①本范例通过可视化模型演示分数减法,特别是通过将整数部分转化为分数部分进行减法运算的过程;②涉及的核心数学概念包括分数减法、通分、整数与分数的转换;③作图要点——使用了 GeoGebra 命令 If, Sequence, Point, Textfield, Polygon, Text, Segment 等,构建了分数减法模型;④适合初中数学教学,帮助学生直观理解分数减法运算。
GeoGebra 命令及参数
If(Defined[minWhole], minWhole, 0) → realMinWholeIf(Defined[minNum] ∧ Defined[minDen], If[Defined[subDen] ∧ Defined[subNum] ∧ b, (minNum * LCM[minDen, subDen] / minDen), minNum], 0) → realMinNumIf(Defined[subDen], If[Defined[minDen] ∧ b, LCM[minDen, subDen], subDen], 1) → realSubDenIf(((¬Defined[minDen]) ∨ minDen ≟ 1) ∧ Defined[realSubDen], realSubDen, If[Defined[minDen], If[Defined[subDen] ∧ b, LCM[minDen, subDen], minDen], 1]) → realMinDenIf(Defined[subWhole], subWhole, 0) → realSubWholeIf(Defined[subNum] ∧ Defined[subDen], If[Defined[minDen] ∧ Defined[minNum] ∧ b, (subNum * LCM[minDen, subDen] / subDen), subNum], 0) → realSubNumSequence(Point[{i, -1 / 2}], i, 0, floor(minuend) - floor(subtrahend)) → subPointsPoint(subPoints) → SubStartingPointSequence(Point[{i, 1 / 2}], i, 0, floor(minuend)) → minWholesPointsTextfield(minWhole) → InputBox1Textfield(minNum) → InputBox2Textfield(minDen) → InputBox3Textfield(subWhole) → InputBox4Textfield(subNum) → InputBox5Textfield(subDen) → InputBox6Polygon((0, 0), (realMinWhole + realMinNum / realMinDen, 0), (realMinWhole + realMinNum / realMinDen, 1), (0, 1)) → minPoly, f, g, h, iPoint(minWholesPoints) → MinStartingPointPolygon(SubStartingPoint + (0, -1 / 2), SubStartingPoint + (realSubWhole + realSubNum / realSubDen, -1 / 2), SubStartingPoint + (realSubWhole + realSubNum / realSubDen, 1 / 2), SubStartingPoint + (0, 1 / 2)) → subPoly, j, k, l, mText(x(MinStartingPoint), (x(MinStartingPoint) / 2, 1.2)) → minWholeTextText(realSubWhole, SubStartingPoint + (realSubWhole / 2, -1)) → subWholeTextSequence(Segment[SubStartingPoint + (i, -1 / 2), SubStartingPoint + (i, 1 / 2)], i, 0, ceil(subtrahend)) → subWholeLinesSequence(Segment[SubStartingPoint + (i, -1 / 2), SubStartingPoint + (i, 1 / 2)], i, realSubWhole, ceil(subtrahend), 1 / realSubDen) → subDenLinesSequence(Segment[(i, 0), (i, 1)], i, x(MinStartingPoint), ceil(minuend), 1 / realMinDen) → minDenLinesSequence(Segment[(i, 0), (i, 1)], i, 0, ceil(minuend)) → minWholeLinesSegment((0, 1), (ceil(minuend), 1)) → topMinSegment((0, 0), (ceil(minuend), 0)) → bottomMinSegment(SubStartingPoint + (0, -0.5), SubStartingPoint + (ceil(subtrahend), -0.5)) → bottomSubSegment(SubStartingPoint + (0, 0.5), SubStartingPoint + (ceil(subtrahend), 0.5)) → topSub
AI 绘图提示语参考
画一个图形表示分数减法,包括两个矩形分别表示被减数和减数,被减数矩形分为若干个单位分数部分,减数矩形也分为单位分数部分。在被减数矩形下方画出减数矩形,用线段表示单位分数部分,用文字标注整数部分和分数部分。
以上提示语为根据原始绘图命令整理而来,仅供参考。