2\(\frac{7}{9}-\frac{12}{13}x=\frac{7}{9}\)

\(x:4\frac{1}{3}=-2,5\)

\(\frac{3}{4}x\frac{1}{2}\)

a) Cho \(A=\frac{1}{5^2}+\frac{1}{6^2}+....+\frac{1}{100^2}\)

C/mR: \(\frac{1}{6}

1) \(\left(\frac{1,5+1-0,5}{2,5+\frac{5}{3}-1,25}+\frac{0,375-0,3+\frac{3}{11}+\frac{3}{12}}{-0,625+0,5-\frac{5}{11}-\frac{5}{12}}\right):\frac{1890}{2005}+115\)

2) A=\(\frac{1,11+0,19-1,3.2}{2,06+0,54}-\left(\frac{1}{3}+\frac{1}{2}\right):2\)

3) A= \(1+\frac{3}{2^3}+\frac{4}{2^4}+...+\frac{100}{2^{100}}\)

Tính : \(A=\frac{2,5-4\left(\frac{5}{2}-1,2\right)+\frac{3}{8}}{4\left(\frac{5}{2}-1,2\right)-\frac{3}{5}:\frac{2}{5}}-\frac{55}{148}\)

Rút gọn \(B=\frac{3^9-2^3.3^7+2^{10}.3^2-2^{13}}{3^{10}-2^2.3^7+2^{10}.3^3-2^{12}}\)

27 *18 * 15 = 

3,8 * 2,5 * 4 =

1,9 * 1,4 * 1,5 =

\(\frac{4}{3}x\frac{5}{4}x\frac{2}{3}=\)

15,5* 6,4 * 10 =

1,75 * 0,4 * 0,8 =

8 * 5 * 4,5 =

2  * 0,5 * 0,75 =

( 15 - 12 ) *10,5 * 8 =

10 * 4,5 *12 =

\(8\frac{2}{7}-\left(1\frac{1}{6}+25\%\right)\)

\(4\frac{3}{4}+\left(-0,37\right)+\left(-1,28\right)+\left(-2,5\right)+3\frac{1}{12}\)

(giải giúp mình với)

Tính:

1,\(\frac{2}{5}+\left(-\frac{4}{5}\right)+\left(-\frac{1}{2}\right)\)

2,\(A=\frac{0,375-0,3+\frac{3}{11}+\frac{3}{12}}{-0,625+0,5-\frac{5}{11}-\frac{5}{12}}+\frac{1,5+1-0,75}{2,5+\frac{5}{3}-1,25}\)

3,\(B=\frac{\frac{1}{3}-\frac{1}{7}-\frac{1}{13}}{\frac{2}{3}-\frac{2}{7}-\frac{2}{13}}.\frac{\frac{1}{3}-0,25+0,2}{1\frac{1}{6}-0,875+0,7}+\frac{6}{7}\)

Bài 1 : Tính giá trị của biểu thức : 

1) \(\left(\frac{12}{32}+\frac{5}{-20}-\frac{10}{24}\right)\): \(\frac{2}{3}\)

2) 4\(\frac{1}{2}\): (2,5 - 3\(\frac{3}{4}\)) + \(\left(\frac{1}{2}\right)\)²