So sánh hai phân số: \(\frac{-7}{31}va\frac{6}{31}\);\(\frac{-97}{128}va\frac{-99}{128}\) ;\(\frac{3}{7}va\frac{-6}{7}\);\(\frac{2}{5}va\frac{4}{5}\)\(\frac{-2}{5}va\frac{13}{5}\)\(\frac{4}{9}va\frac{7}{9}\)\(\frac{5}{12}va\frac{7}{12}\)\(\frac{-7}{15}va\frac{-8}{15}\)\(\frac{-2}{5}va\frac{4}{5}\)\(\frac{4}{7}va\frac{3}{7}\)\(\frac{-11}{13}va\frac{-15}{13}\)\(\frac{-2}{7}va\frac{-4}{14}\)\(\frac{_{-5}}{7}va\frac{-10}{7}\)\(\frac{-13}{5}va\frac{1}{5}\)\(\frac{-6}{7}va\frac{-3}{7}\)\(\frac{3}{7}va\frac{5}{7}\)\(\frac{-7}{9}va\frac{-5}{9}\)\(\frac{-3}{7}va\frac{-5}{7}\)\(\frac{-13}{9}va\frac{1}{9}\) so sánh số cùng mẫu số \(\frac{-7}{13};\frac{-4}{13}\) \(\frac{1}{7};\frac{-4}{-7}\)

Tìm x \(\in\)Z biết 

a, \(\frac{1}{3}\)+ \(\frac{-2}{5}\)+ \(\frac{1}{6}\)+ \(\frac{-1}{5}\)\(\le\)x < \(\frac{-3}{4}\)+\(\frac{2}{7}\)+ \(\frac{3}{5}\)+ \(\frac{5}{7}\)+ \(\frac{-1}{4}\)

b, \(\frac{5}{17}\)+ \(\frac{-4}{9}\)+ \(\frac{-20}{31}\)+ \(\frac{12}{17}\)+ \(\frac{-11}{31}\)< x < \(\frac{-3}{7}\)+ \(\frac{7}{15}\)+ \(\frac{4}{-7}\)+ \(\frac{8}{15}\) + \(\frac{2}{3}\)

BÀI ÔN SỐ HỌC

1. Thực hiện mỗi phép tính sau bằng 2 cách:

a)\(3\frac{4}{9}+5\frac{1}{6}\)

Ví dụ :

Cách 1: \(3\frac{4}{9}+5\frac{1}{6}=\frac{31}{9}+\frac{31}{6}=\frac{62}{18}+\frac{93}{18}=\frac{155}{18}=8\frac{11}{18}\)

Cách 2:\(3\frac{4}{9}+5\frac{1}{6}=3\frac{8}{18}+5\frac{3}{18}=8\frac{11}{18}\)

b)\(8\frac{1}{14}-6\frac{3}{7}\)

c)\(7-3\frac{6}{7}\)

2. Áp dụng tính chất phép tính & qui tắc dấu ngoặc để tính giá trị các biểu thức sau:

a)A =\(11\frac{3}{13}-\left(3\frac{4}{7}+6\frac{3}{13}\right)\)

b)B =\(\left(7\frac{4}{9}+3\frac{8}{13}\right)-5\frac{4}{3}\)

c)C =\(\frac{-2}{7}.\frac{5}{11}+\frac{-2}{7}.\frac{6}{11}+5\frac{4}{7}\)

d)D =\(0,7.1\frac{3}{5}.30.0,375.\frac{4}{7}\)

3.Tìm các số nghịch đảo của các số sau : \(\frac{4}{7};6\frac{3}{8};\frac{-3}{17};0.37\)

4.Tìm x, biết :

0,5-\(\frac{2}{3}x=\frac{5}{12}\)

tính nhanh:

a/ A=\(\frac{17}{5}\).\(\frac{-31}{125}\).\(\frac{1}{2}\).\(\frac{10}{17}\).\(\frac{-1}{2^3}\)

b/B=\(\frac{1}{4}\).\(\frac{9}{11}\)+\(\frac{7}{4}\).\(\frac{-1}{11}\)-\(\frac{5}{11}\).\(\frac{1}{4}\)

c/C=(1-\(\frac{1}{7}\)) . (1-\(\frac{2}{7}\)).(1-\(\frac{3}{7}\))...(1-\(\frac{20}{7}\))

p/s:các bn nhớ ghi cách giải và đáp số nka

1,Tính

\(\frac{5^2}{6}\)+\(\frac{5^2}{66}\)+...+\(\frac{5^2}{806}\)

2,Tìm x

a, (\(\frac{2}{11.13}\)+\(\frac{2}{13.15}\)+...+\(\frac{2}{19.21}\)) - x +\(\frac{221}{231}\)=\(\frac{4}{3}\)

b, \(\frac{1}{3.4}\)+\(\frac{1}{4.5}\)+\(\frac{1}{5.6}\)+\(\frac{1}{6.7}\)+...+\(\frac{1}{x.\left(x+1\right)}\)=\(\frac{3}{10}\)

3, Chứng minh dãy số nhỏ hơn 1

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

16 tính bằng cách hợp lí 

a) (  \(\frac{1}{4}\)+ \(\frac{-5}{13}\)) + ( \(\frac{2}{11}+\frac{-8}{13}+\frac{3}{4}\))

b) ( \(\frac{21}{31}+\frac{-16}{7}\)) +(  \(\frac{44}{53}\)+ \(\frac{10}{31}\)) +\(\frac{9}{53}\)
c) \(\frac{-5}{7}+\frac{3}{4}+\frac{-1}{5}+\frac{-2}{7}+\frac{1}{4}\)

d) \(\frac{-3}{31}+\frac{-6}{17}+\frac{1}{25}+\frac{-28}{31}+\frac{-11}{17}+\frac{-1}{5}\)

Tìm x:

a) 5\(\frac{4}{7}\): x =13

b) \(\frac{4}{7}\)x=\(\frac{9}{8}\)-0,125

c) \(\frac{2}{3}\)x-\(\frac{1}{2}\)=\(\frac{1}{10}\)

d) \(\frac{1}{3}\)x-0,5x = -1\(\frac{1}{4}\)

e) \(\frac{-5}{6}\)- x = \(\frac{7}{12}\)+ \(\frac{-1}{3}\)

f) \(\frac{x+2}{3}\)=\(\frac{x-2}{2}\)

g) \(\frac{2}{5}\)- \(\frac{1}{5}\): x = -25%

h) (2\(\frac{4}{5}\)x - 50): \(\frac{2}{3}\)= 51

i) \(\frac{2}{3}\)x -\(\frac{1}{2}\)x =\(\frac{5}{12}\)

j) \(\frac{7}{2}\)- |2x -\(\frac{3}{4}\)| = -\(\frac{7}{4}\)

k) (x : 6\(\frac{2}{7}\)+\(\frac{3}{7}\)) :2\(\frac{1}{5}\)-\(\frac{3}{7}\)= -2

l) (x +\(\frac{1}{5}\))² +\(\frac{17}{25}\)=\(\frac{26}{25}\)

m) (x +\(\frac{1}{2}\))(\(\frac{2}{3}\)- 2x) =0

Mọi người ơi giúp mình nhanh nha.

Ai giúp mình thì mình sẽ tick cho.