Question

da uma ajudinha ai ;)

Answer 1

Quando os denominadores são diferentes, deve-se primeiramente reduzir as frações para o mesmo denominador (calcular mmc dos denominadores).


a) $\dfrac{1}{2}+\dfrac{1}{3}$

$=\dfrac{3}{6}+\dfrac{2}{6}\\\\\\ =\dfrac{3+2}{6}\\\\\\ =\dfrac{5}{6}$

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b) $\dfrac{1}{2}+\dfrac{1}{3}+\dfrac{5}{6}$

$=\dfrac{3}{6}+\dfrac{2}{6}+\dfrac{5}{6}\\\\\\ =\dfrac{3+2+5}{6}\\\\\\ =\dfrac{10}{6}\begin{array}{c}^{\div 2}\\^{\div 2} \end{array}\\\\\\ =\dfrac{5}{3}$

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c) $\dfrac{1}{2}-\dfrac{1}{3}$

$=\dfrac{3}{6}-\dfrac{2}{6}\\\\\\ =\dfrac{3-2}{6}\\\\\\ =\dfrac{1}{6}$

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d) $\dfrac{5}{6}-\dfrac{1}{2}$

$=\dfrac{5}{6}-\dfrac{3}{6}\\\\\\ =\dfrac{5-3}{6}\\\\\\ =\dfrac{2}{6}\begin{array}{c}^{\div 2}\\^{\div 2} \end{array}\\\\\\ =\dfrac{1}{3}$

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e) $\dfrac{7}{5}-\dfrac{6}{5}$

$=\dfrac{7-6}{5}\\\\\\ =\dfrac{1}{5}$


Bons estudos! :-)