\(\dfrac{-5}{7}.\dfrac{2}{11}+\dfrac{-5}{7}.\dfrac{9}{14}+1\dfrac{5}{7}\)
\(=\dfrac{-5}{11}.\dfrac{2}{7}+\dfrac{-5}{11}.\dfrac{9}{7}+\dfrac{12}{7}\)
\(=\dfrac{-5}{11}\left(\dfrac{2}{7}+\dfrac{9}{7}\right)+\dfrac{12}{7}\)
\(=\dfrac{-5}{11}.\dfrac{11}{7}+\dfrac{12}{7}\)
\(=\dfrac{-5}{7}+\dfrac{12}{7}=\dfrac{7}{7}=1\)
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
3) \(11\dfrac{1}{4}-\left(2\dfrac{5}{7}+5\dfrac{1}{4}\right)\)
4) \(\dfrac{11}{125}-\dfrac{17}{18}-\dfrac{5}{7}+\dfrac{4}{9}+\dfrac{17}{14}\)
BT2: Tính nhanh
11) \(-\dfrac{5}{7}-\left(-\dfrac{5}{67}\right)+\dfrac{13}{30}+\dfrac{1}{2}+\left(-1\dfrac{5}{6}\right)+1\dfrac{3}{14}-\left(-\dfrac{2}{5}\right)\)
12) \(\dfrac{-1}{4}.13\dfrac{9}{11}-0.25.6\dfrac{2}{11}\)
Các bạn giúp mình với nhé
Tính nhanh :
\(\dfrac{-5}{7}.\dfrac{2}{11}+\dfrac{-5}{7}.\dfrac{9}{14}+\dfrac{6}{7}\)
BT2: Tính nhanh
13) \(\dfrac{4}{9}:\left(-\dfrac{1}{7}\right)+6\dfrac{5}{9}:\left(-\dfrac{1}{7}\right)\)
14) \(\left(-\dfrac{3}{4}+\dfrac{5}{13}\right):\dfrac{2}{7}-\left(2\dfrac{1}{4}+\dfrac{8}{13}\right):\dfrac{2}{7}\)
*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)\(\dfrac{4}{9}:\left(\dfrac{-1}{7}\right)+6\dfrac{5}{9}:\left(\dfrac{-1}{7}\right)\)
A=15.\(\left(\dfrac{3}{5}-\dfrac{2}{3}\right)+1\)
\(B=1-\dfrac{13}{9}:\dfrac{8}{19}+\dfrac{-11}{9}:\dfrac{8}{19}\)
\(C=\dfrac{-5}{7}.\dfrac{2}{11}+\dfrac{-5}{7}.\dfrac{9}{11}+1\dfrac{5}{7}\)
\(D=\dfrac{6}{7}+\dfrac{5}{8}:5-\dfrac{3}{16}.\left(-2\right)^2\)
tính giá trị của biểu thức
Tính hợp lí
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)\(\dfrac{4}{9}:\left(-\dfrac{1}{7}\right)+6\dfrac{5}{9}:\left(-\dfrac{1}{7}\right)\)
Tính nhanh
\(\dfrac{-5}{7}\). \(\dfrac{2}{11}\)+ \(\dfrac{-5}{11}\). \(\dfrac{9}{7}\)- \(1\dfrac{5}{7}\)
