Bài 1 trang 10 SGK Toán 5

Tính:

a) \( \dfrac{6}{7}+\dfrac{5}{8}\) ;                             b) \( \dfrac{3}{5}-\dfrac{3}{8}\) ; 

c) \( \dfrac{1}{4}+\dfrac{5}{6}\);                              d) \( \dfrac{4}{9}-\dfrac{1}{6}\) .

a) \( \dfrac{6}{7}+\dfrac{5}{8}\) \( =\dfrac{48}{56}+\dfrac{35}{56}=\dfrac{83}{56}\) ;

b) \( \dfrac{3}{5}-\dfrac{3}{8}\) \( =\dfrac{24}{40}-\dfrac{15}{40}=\dfrac{9}{40}\) ;

c) \( \dfrac{1}{4}+\dfrac{5}{6}\) \( =\dfrac{6}{24}+\dfrac{20}{24}=\dfrac{26}{24}=\dfrac{13}{12}\) ;

d) \( \dfrac{4}{9}-\dfrac{1}{6}\) \( =\dfrac{24}{54}-\dfrac{9}{54}=\dfrac{15}{54}=\dfrac{5}{18}\).