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Aufgaben zur Umwandlung von Brüchen in Dezimalzahlen und umgekehrt.

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Zahlumwandlungen

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Schreibe den gewöhnlichen Bruch als Dezimalzahl oder umgekehrt.

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Lösung zu a):

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Eine Möglichkeit ist es, durch schriftliche Division das Ergebnis von $\\var{Zaehler}:\\var{nenner}$ zu berechnen.

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Eine andere Möglichkeit ist es, mit der Umwandlung in einen Dezimalbruch zu arbeiten. Wir müssen jetzt schauen, dass wir eine Zehnertpotenz finden, die ein ganzzahliges Vielfaches von $\\var{Nenner}$ ist. Dazu bestimmen wird die Primfaktorzerlegung von $\\var{Nenner}$ das ist $2^\\var{p2}\\cdot5^\\var{p5}$.

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Wir wählen jetzt die Zehnerpotenz $10^\\var{max(p2,p5)}$ aus, die als Exponent das Maximum der Exponenten von $2$ und $5$ hat. Der resultierende Dezimalbruch ist also: $\\frac{\\var{Zaehler}\\cdot\\var{10^max(p2,p5)/Nenner}}{\\var{Nenner}\\cdot\\var{10^max(p2,p5)/Nenner}}=\\frac{\\var{Zaehler*10^max(p2,p5)/Nenner}}{\\var{10^max(p2,p5)}}=\\var{formatnumber(Bruch,\"eu\")}$.

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Lösung zu b):

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Wir ermitteln eine Zehnerpotenz, die so viele Nullen hat, wie unser Dezimalbruch Nachkommastellen, das ist $1000$. Als Dezimalbruch ergibt sich zunächst $\\frac{\\var{Zaehler2}}{\\var{Nenner2}}$. Diesen Bruch kann man noch kürzen und erhält dann als Ergebnis $\\var[fractionNumbers]{Dezimalbruch}$.

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Lösung zu c):

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Hier musst Du die schriftliche Division bis zur 4. Nachkommastelle durchführen und dann passend auf- oder abrunden.

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$\\frac{\\var{Zaehler3}}{\\var{nenner3}}=$[[0]]

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