tính nhanh :
a) \(6\dfrac{5}{7}-\left(1\dfrac{3}{4}+2\dfrac{5}{7}\right)\)
b) \(7\dfrac{5}{11}-\left(2\dfrac{3}{7}+3\dfrac{5}{11}\right)\)
c) \(\dfrac{1}{3}.\dfrac{4}{5}+\dfrac{1}{3}.\dfrac{6}{5}-\dfrac{4}{3}\)
d) \(\left(\dfrac{-4}{5}+\dfrac{4}{3}\right)+\left(\dfrac{-5}{4}+\dfrac{14}{5}\right)-\dfrac{7}{3}\)
e) \(\dfrac{-5}{7}.\dfrac{2}{11}+\dfrac{-5}{7}.\dfrac{9}{14}+1\dfrac{5}{7}\)
BT2: Tính nhanh
7) \(\left(-\dfrac{1}{2}\right)-\left(-\dfrac{3}{5}\right)+\left(-\dfrac{1}{9}\right)+\dfrac{1}{71}-\left(-\dfrac{2}{7}\right)+\dfrac{4}{35}-\dfrac{7}{18}\)
8)\(\left(3-\dfrac{1}{4}+\dfrac{2}{3}\right)-\left(5-\dfrac{1}{3}-\dfrac{6}{5}\right)-\left(6-\dfrac{7}{4}+\dfrac{3}{2}\right)\)
Tính giá trị biểu thức
\(\dfrac{\dfrac{2}{3}.\dfrac{7}{15}-\dfrac{2}{3}.\dfrac{5}{27}}{\dfrac{-9}{9}.\dfrac{7}{15}+\dfrac{4}{9}.\dfrac{5}{27}}\)
*Phép chia
a)\(11\dfrac{1}{4}-\left(2\dfrac{5}{7}+5\dfrac{1}{4}\right)\)
b)\(\left(8\dfrac{5}{11}+3\dfrac{5}{8}\right)-3\dfrac{5}{11}\)
c)\(\dfrac{-1}{4}.13\dfrac{9}{11}-0,25.6\dfrac{2}{11}\)
d)\(\dfrac{4}{9}:\left(\dfrac{-1}{7}\right)+6\dfrac{5}{9}:\left(\dfrac{-1}{7}\right)\)
1. tìm x thuộc z biết \(\dfrac{x}{-12}\)=\(\dfrac{-3}{2}\)
2 tính
a,\(\dfrac{-7}{9}\times\dfrac{6}{11}+\dfrac{-2}{9}\)
b,\(\dfrac{-4}{7}:2=\)
c,115- (24-5\(\times\)3)
d,\(\dfrac{-3}{7}\times\dfrac{5}{9}+\dfrac{4}{9}\times\dfrac{-3}{7}+2\dfrac{3}{7}\)
e,\(\dfrac{1}{4\times5}+\dfrac{1}{6\times7}+......\dfrac{1}{79\times80}\)
Thực hiện phép tính
a) \(\dfrac{1}{2}.\left(\dfrac{2}{9}+\dfrac{3}{7}-\dfrac{5}{27}\right)\) b) \(\left(\dfrac{-5}{28}+1,75+\dfrac{8}{35}\right):\left(-3\dfrac{9}{20}\right)\)
c) \(\dfrac{1}{3}.\dfrac{5}{7}-\dfrac{7}{27}.\dfrac{36}{14}\) d) \(70,5-528:\dfrac{15}{2}\)
Bài 3: Tính(hợp lí nếu có thể)
a) \(\dfrac{-7}{9}\)+\(\dfrac{5}{12}\)-\(\dfrac{13}{18}\)
b)\(\dfrac{11}{9}\)x\(\dfrac{15}{4}\)-\(\dfrac{11}{4}\)x\(\dfrac{7}{9}\)-\(\dfrac{11}{9}\)x\(\dfrac{5}{4}\)
c)(\(15\dfrac{9}{7}\)+\(6\dfrac{2}{3}\))-\(5\dfrac{5}{9}\)
d)\(\dfrac{5}{6}\)-\(\dfrac{1}{3}\)-\(\dfrac{2}{-18}\)
e)(\(6\dfrac{4}{9}\)+\(3\dfrac{7}{11}\))-\(4\dfrac{4}{9}\)
f)(\(11\dfrac{2}{7}\)+\(3\dfrac{2}{5}\))-\(7\dfrac{2}{7}\)
tính
a,\((15.\dfrac{3}{5}-19\dfrac{7}{9})-(13\dfrac{3}{5}-17\dfrac{7}{9})\)
b,\([\dfrac{6}{5}-(\dfrac{3}{7}-2\dfrac{1}{7})\div\dfrac{4}{7}].(-\dfrac{3}{5})+\dfrac{2}{3}\div(-\dfrac{5}{6})\)
giúp mình nhé
BT2: Tính nhanh
13) \(\dfrac{4}{9}:\left(-\dfrac{1}{7}\right)+6\dfrac{5}{9}:\left(-\dfrac{1}{7}\right)\)
14) \(\left(-\dfrac{3}{4}+\dfrac{5}{13}\right):\dfrac{2}{7}-\left(2\dfrac{1}{4}+\dfrac{8}{13}\right):\dfrac{2}{7}\)