Bài 4:
a: \(\dfrac{6}{7}+\dfrac{5}{8}=\dfrac{48+35}{56}=\dfrac{83}{56}\)
b: \(\dfrac{4}{9}-\dfrac{1}{6}=\dfrac{24-9}{54}=\dfrac{15}{54}=\dfrac{5}{18}\)
\(1,\\ a,=2,7\\ =4,15\\ =13,51\\ =0,047\\ b,=3,8\\ =15,6\\ =47,625\\ c,=12,3\\ =12,38\\ =0,2301\\ 2,\\ a,54,76\\ b,12,035\\ c,7,0057\\ d,21,47\\ 4,\\ a,=\dfrac{83}{56}\\ b,=\dfrac{5}{18}\\ c,=\dfrac{2}{15}\\ d,=\dfrac{5}{4}\)