Bài 107 (Sách giáo khoa trang 48)

Gửi bởi: Sách Giáo Khoa Vào 26 tháng 12 2018 lúc 11:14:37

Tính :

a) \(\dfrac{1}{3}+\dfrac{3}{8}-\dfrac{7}{12}\)

b) \(\dfrac{-3}{14}+\dfrac{5}{8}-\dfrac{1}{2}\)

c) \(\dfrac{1}{4}-\dfrac{2}{3}-\dfrac{11}{18}\)

d) \(\dfrac{1}{4}+\dfrac{5}{12}-\dfrac{1}{13}-\dfrac{7}{8}\)

a) \(\dfrac{1}{3}+\dfrac{3}{8}-\dfrac{7}{12}\)

\(=\dfrac{17}{24}-\dfrac{7}{12}\)

\(=\dfrac{1}{8}\)

b) \(\dfrac{-3}{14}+\dfrac{5}{8}-\dfrac{1}{2}\)

\(=\dfrac{23}{56}-\dfrac{1}{2}\)

\(=\dfrac{-5}{56}\)

c) \(\dfrac{1}{4}-\dfrac{2}{3}-\dfrac{11}{18}\)

\(=\dfrac{-5}{12}-\dfrac{11}{18}\)

\(=\dfrac{-37}{36}\)

d) \(\dfrac{1}{4}+\dfrac{5}{12}-\dfrac{1}{13}-\dfrac{7}{8}\)

\(=\dfrac{2}{3}-\dfrac{1}{13}-\dfrac{7}{8}\)

\(=\dfrac{23}{39}-\dfrac{7}{8}\)

\(=\dfrac{-89}{312}\)