Đề bài

Tính: a) \(\dfrac{{ - 1}}{{13}} + \dfrac{9}{{13}}\) b) \(\dfrac{{ - 3}}{8} + \dfrac{5}{{12}}\)

Lời giải chi tiết

a) \(\dfrac{{ - 1}}{{13}} + \dfrac{9}{{13}}\)\( = \dfrac{{ - 1 + 9}}{{13}} = \dfrac{8}{{13}}\)b) \(\dfrac{{ - 3}}{8} + \dfrac{5}{{12}}\)\(\begin{array}{l} = \dfrac{{ - 3.3}}{{8.3}} + \dfrac{{5.2}}{{12.2}}\\ = \dfrac{{ - 9}}{{24}} + \dfrac{{10}}{{24}} = \dfrac{1}{{24}}\end{array}\)

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