Ôn tập toán 7
Các câu hỏi tương tự
Tính giá trị của biểu thức sau:
A = \(\dfrac{1}{2}\left(1+\dfrac{1}{1.3}\right)\left(1+\dfrac{1}{2.4}\right)\left(1+\dfrac{1}{3.5}\right)...\left(1+\dfrac{1}{2015.2017}\right)\)
Tính giá trị của biểu thức sau:
A= \(\dfrac{1}{2}\left(1+\dfrac{1}{1.3}\right)\left(1+\dfrac{1}{2.4}\right)\left(1+\dfrac{1}{3.5}\right)...\left(1+\dfrac{1}{2015.2017}\right)\)
tính \(S=\left(-\dfrac{1}{7}\right)^0+\left(-\dfrac{1}{7}\right)^1+\left(-\dfrac{1}{7}\right)^2+...+\left(-\dfrac{1}{7}\right)^{2007}\)
1.Tính
\(\left(1-\dfrac{1^2}{100}\right)\left(1-\dfrac{2^2}{100}\right)\left(1-\dfrac{3^2}{100}\right)...\left(1-\dfrac{2018^2}{100}\right)\)
2.S=\(\dfrac{1}{4}+\dfrac{2}{4^2}+\dfrac{3}{4^3}+...+\dfrac{2017}{4^{2017}}\)
Chứng minh rằng S <\(\dfrac{1}{2}\)
Phương trình : \(\dfrac{1}{\left(x-1\right)\left(x-2\right)}+\dfrac{1}{\left(x-2\right)\left(x-3\right)}=\dfrac{1}{\left(x-3\right)\left(x-4\right)}+\dfrac{1}{\left(x-1\right)\left(x-4\right)}\)
\(\left|x+\dfrac{1}{5}\right|:\dfrac{9}{10}\)
\(\left|x-\dfrac{1}{2}\right|+\left|x+y\right|=0\)
\(\left|2x\right|-\left|3.5\right|=\left|-6.5\right|\)
\(\left|x-1.7\right|=2.3\)
Cho C = \(\left(\dfrac{1}{2^2}-1\right)\left(\dfrac{1}{3^2}-1\right)...\left(\dfrac{1}{10^2}-1\right)xy^2z^3t^4\)
D= \(\left(1+\dfrac{7}{9}\right)\left(1+\dfrac{7}{20}\right)\left(1+\dfrac{7}{33}\right)...\left(1+\dfrac{7}{180}\right)x^4y^3z^2t\)
Tính E biết E = \(\dfrac{90}{11^2}CD\)
Thực hiện các phép tính :
a) 9,6.2dfrac{1}{2}-left(2.125-1dfrac{5}{12}right):dfrac{1}{4}
b) dfrac{5}{18}-1,456:dfrac{7}{25}+4,5.dfrac{4}{5}
c) left(dfrac{1}{2}+0,8-1dfrac{1}{3}right)left(2,3right)+4dfrac{7}{25}-1,28
d) left(-5right).12:left[left(-dfrac{1}{4}right)+dfrac{1}{2}:left(-2right)right]+1dfrac{1}{3}
Đọc tiếp
Thực hiện các phép tính :
a) \(9,6.2\dfrac{1}{2}-\left(2.125-1\dfrac{5}{12}\right):\dfrac{1}{4}\)
b) \(\dfrac{5}{18}-1,456:\dfrac{7}{25}+4,5.\dfrac{4}{5}\)
c) \(\left(\dfrac{1}{2}+0,8-1\dfrac{1}{3}\right)\left(2,3\right)+4\dfrac{7}{25}-1,28\)
d) \(\left(-5\right).12:\left[\left(-\dfrac{1}{4}\right)+\dfrac{1}{2}:\left(-2\right)\right]+1\dfrac{1}{3}\)
Bài 1: Tính
a) \(\dfrac{1}{5}:\dfrac{1}{10}-\dfrac{1}{3}\left(\dfrac{6}{5}-\dfrac{9}{4}\right)\)
b) \(\dfrac{1}{2}\left(\dfrac{4}{3}+\dfrac{2}{5}\right)-\dfrac{3}{4}\left(\dfrac{8}{9}+\dfrac{16}{3}\right)\)
c) \(\dfrac{6}{7}:\left(\dfrac{3}{26}-\dfrac{3}{13}\right)+\dfrac{6}{7}\left(\dfrac{1}{10}-\dfrac{8}{5}\right)\)