tinh
\(A=\left(\frac{1}{7}+\frac{1}{23}-\frac{1}{1009}\right):\left(\frac{1}{23}+\frac{1}{7}-\frac{1}{1009}+\frac{1}{7}.\frac{1}{23}.\frac{1}{1009}\right)+1:\left(30.1009-160\right)\)
\(\left(1-\dfrac{1}{2}\right)\left(1-\dfrac{1}{3}\right)\left(1-\dfrac{1}{4}\right)\left(1-\dfrac{1}{5}\right)\left(1-\dfrac{1}{6}\right)\left(1-\dfrac{1}{7}\right)\left(1-\dfrac{1}{8}\right)\left(1-\dfrac{1}{9}\right)\left(1-\dfrac{1}{10}\right)\)
tính
\(G=\left(1-\dfrac{1}{7}\right)\left(1-\dfrac{2}{7}\right)\left(1-\dfrac{3}{7}\right)...\left(1-1\dfrac{2}{7}\right)\left(1-1\dfrac{3}{7}\right)\)
a) \(\dfrac{\left(3+\dfrac{1}{6}\right)-\dfrac{2}{5}}{\left(5-\dfrac{1}{6}\right)+\dfrac{7}{10}}\)
b) \(\dfrac{\left(4,08-\dfrac{2}{25}\right):\dfrac{4}{17}}{\left(6\dfrac{5}{9}-3\dfrac{1}{4}\right).2\dfrac{2}{7}}\)
c) \(\dfrac{2-\dfrac{1}{4}+\dfrac{1}{3}-\dfrac{3}{5}}{3-\dfrac{1}{5}-\dfrac{5}{3}}\)
Tính hợp lí:
\(A=(1+\dfrac{7}{9})+\left(1+\dfrac{7}{20}\right)+\left(1+\dfrac{7}{33}\right)+...+\left(1+\dfrac{7}{2900}\right)\)
1, so sánh A;B biết: A=\(\left(\dfrac{\left(3\cdot\dfrac{2}{15}+\dfrac{1}{5}\right):2\cdot\dfrac{1}{2}}{\left(5\cdot\dfrac{3}{7}-2\cdot\dfrac{1}{4}\right):\dfrac{443}{56}}\right);B=\dfrac{1,2:\left(1\cdot\dfrac{1}{5}.1\cdot\dfrac{1}{4}\right)}{0,32+\dfrac{2}{25}}\)
tính giá trị biểu thức sau:
\(B=\left(1-\dfrac{1}{7}\right).\left(1-\dfrac{2}{7}\right).\left(1-\dfrac{3}{7}\right)...\left(1-\dfrac{2011}{7}\right)\)
tính
\(F=\left(1-\dfrac{1}{5}\right).\left(1-\dfrac{1}{6}\right).\left(1-\dfrac{1}{7}\right)...\left(1-\dfrac{1}{100}\right)\)
Bài 1: Tìm x,y biết:
a) \(\left|x-\dfrac{2}{3}\right|+\left|y+x\right|=0\) b) \(\left(x-2y\right)^2+\left|x+\dfrac{1}{6}\right|=0\)
c) \(\left|3x+5y\right|+\left|y-2\right|=0\)
Bài 2: Tìm giá trị nhỏ nhất
A= \(\left|5x+1\right|-\dfrac{3}{8}\) B= \(\left|2-\dfrac{1}{6}x\right|+0,25\)
Bài 3: Tìm giá trị lớn nhất
A= 2018 - \(\left|x+2019\right|\) B= -10 - \(\left|2x-\dfrac{1}{1009}\right|\)