\(\dfrac{1\cdot3\cdot5+2\cdot6\cdot10+4\cdot12\cdot20+7\cdot21\cdot35}{1\cdot5\cdot7+2\cdot10\cdot14+4\cdot20\cdot28+7\cdot35\cdot45}\)
=\(\dfrac{3+6+12+21\cdot35}{14+28+7\cdot45}\)
=\(\dfrac{450}{119}\)
Vì \(\dfrac{450}{119}>1\) mà \(1>\dfrac{303}{708}\)
\(\Rightarrow\)\(\dfrac{450}{119}>\dfrac{303}{708}\)
\(\dfrac{2}{7}.\dfrac{4}{5}+\dfrac{3}{5}.\dfrac{2}{7}-\dfrac{1}{5}\)
Tính bằng hai cách :
a) \(2\dfrac{1}{4}+1\dfrac{1}{6}\)
b) \(7\dfrac{1}{8}-5\dfrac{3}{4}\)
c) \(4-2\dfrac{6}{7}\)
Áp dụng tính chất các phép tính và quy tắc dấu ngoặc để tính giá trị các biểu thức sau :
\(A=11\dfrac{3}{13}-\left(2\dfrac{4}{7}+5\dfrac{3}{13}\right)\)
\(B=\left(6\dfrac{4}{9}+3\dfrac{7}{11}\right)-4\dfrac{4}{9}\)
\(C=\dfrac{-5}{7}.\dfrac{2}{11}+\dfrac{-5}{7}-\dfrac{9}{11}+1\dfrac{5}{7}\)
\(D=0,7.2\dfrac{2}{3}.20.0,375.\dfrac{5}{28}\)
\(E=\left(-6,17+3\dfrac{5}{9}-2\dfrac{36}{97}\right)\left(\dfrac{1}{3}-0,25-\dfrac{1}{12}\right)\)
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) \(\dfrac{1}{4}+\dfrac{5}{12}-\dfrac{1}{13}-\dfrac{7}{8}\)
Thực hiện phép tính( tính nhanh nếu có thể)
a, \(\left(-\dfrac{1}{2}\right)^2.\dfrac{7}{4}:\left(\dfrac{5}{8}-1\dfrac{3}{16}\right)\)
b, \(17\dfrac{6}{11}.\dfrac{4}{27}-8\dfrac{6}{11}:\dfrac{27}{4}+350\%\)
\(\left|2x-\dfrac{3}{7}\right|-\dfrac{1}{2}=\dfrac{3}{4}\)
tính
a) (\(2\dfrac{5}{6}+1\dfrac{4}{9}\)):(\(10\dfrac{1}{12}\)-9\(\dfrac{1}{2}\))
b) \(\dfrac{0,8:\left(\dfrac{4}{5}:1,25\right)}{0,64-\dfrac{1}{25}}\)
c) \(\dfrac{\left(100-\dfrac{2}{25}\right):\dfrac{4}{7}}{\left(6\dfrac{5}{9}-3\dfrac{1}{4}\right).2\dfrac{2}{27}}\) + (1,2 . 0,5) : \(\dfrac{3}{5}\)
a)\(\left(\dfrac{17}{10}+7-8,7\right)\div\left(\dfrac{23}{4}-\dfrac{11}{4}+\dfrac{9}{25}\right)\times\left(12,98\times0,25\right)+12,5\)
b)\(1\dfrac{2}{24}\times5\dfrac{2}{5}\times2\times3\dfrac{7}{9}\times2\times\dfrac{2}{17}\)
Tìm x
a) \(\left[\left(6\dfrac{3}{7}-\dfrac{0,75.x-2}{0,35}\right).2,8+1,75\right]:0,05=2,35\)
b) \(\dfrac{3}{5}-\dfrac{2}{7}< \dfrac{2}{3}.x+\dfrac{3}{4}< \dfrac{1}{2}+\dfrac{7}{9}\)