a) \(14:\left(14\frac{1}{2}-6\frac{5}{8}\right)+14\frac{1}{2}.\frac{2}{3}\)

b) \(\left(15-14\frac{3}{7}\right).56,7-1\frac{7}{8}:\left(20-19,25\right)\)

c) \(\left(-3,2\right).\frac{-15}{64}+\left(0,8-2\frac{4}{15}\right):3\frac{3}{2}\)

d) \(1\frac{13}{15}.0,75-\left(\frac{104}{5\%}+2\right).\frac{24}{47}-3\frac{12}{13}:3\)

Bài 1: tính nhanh

a)\(6\frac{4}{5}-\left(1\frac{2}{3}+3\frac{4}{5}\right)\)

b)\(\left(\frac{-4}{5}+\frac{4}{3}\right)+\left(\frac{-5}{4}+\frac{14}{5}\right)-\frac{7}{3}\)

c)\(\frac{8}{3}.\frac{2}{5}.\frac{3}{8}.10\frac{19}{92}\)

d)\(\frac{-5}{7}.\frac{2}{11}+\frac{-5}{7}.\frac{9}{14}+1\frac{5}{7}\)

e)\(\frac{12}{19}.\frac{7}{15}.\frac{-13}{17}.\frac{19}{12}.\frac{17}{13}\)

BÀI 1:CM PHÂN SỐ TỐI GIẢN:

a)\(\frac{n}{n+1}\)   b) \(\frac{2n+3}{3n+1}\)c)\(\frac{12n+1}{30n+2}\)

Bài 2:CTR

\(\frac{9}{20}< \frac{1}{2^2}+\frac{1}{3^2}+\frac{1}{4^2}+...+\frac{1}{100^2}< 1\)

Bài 3:Cho   \(A=\frac{3}{11}+\frac{3}{12}+\frac{3}{13}+\frac{3}{14}+\frac{3}{15}\)CMR \(A\notinℕ\)

Bài 1: So sánh:

A=\(\frac{2}{3}\)+ \(\frac{14}{15}\)+ \(\frac{34}{35}\)+ \(\frac{62}{63}\)+ \(\frac{98}{99}\)+ \(\frac{142}{143}\)+ \(\frac{194}{195}\)

B= 5+ \(\frac{1}{2^2}\)+ \(\frac{1}{3^3}\)+ \(\frac{1}{4^4}\)+ \(\frac{1}{5^5}\)+ \(\frac{1}{6^6}\)+ \(\frac{1}{7^7}\)

Bài 2: Chứng minh:

C=\(\frac{1}{5}\)+ \(\frac{1}{13}\)+ \(\frac{1}{14}\)+ \(\frac{1}{15}\)+ \(\frac{1}{61}\)+\(\frac{1}{62}\)+ \(\frac{1}{63}\)< \(\frac{1}{2}\)

Bài 5 : Chững minh rẳng :
a) S= \(\frac{3}{10}+\frac{3}{11}+\frac{3}{12}+\frac{3}{13}+\frac{3}{14}\) CMR :1< S <2
b) \(\frac{1}{4^2}+\frac{1}{6^2}+\frac{1}{8^2}+\frac{1}{10^2}+...+\frac{1}{\left(2n\right)^2}< \frac{1}{4}\)
c) \(\frac{3}{4}+\frac{8}{9}+\frac{15}{16}+...+\frac{2499}{2500}>48\)
d) \(\frac{1}{5}+\frac{1}{13}+\frac{1}{14}+\frac{1}{15}+\frac{1}{61}+\frac{1}{62}+\frac{1}{63}< \frac{1}{2}\)
Bài :So sánh phân số sau:
a)\(\frac{1985.1987-1}{1980+1985.1986}và1\)
b) A= \(\frac{13^{15}+1}{13^{16}+1}\)và B = \(\frac{13^{16}+1}{13^{17}+1}\)
c)\(\frac{18}{53}và\frac{26}{79}\)
d)\(\frac{5}{8}và\frac{14}{17}\)
e)\(\frac{1}{5^{199}}và\frac{1}{3^{300}}\)
g)\(\frac{1}{3^{17}}và\frac{1}{5^{10}}\)
h) \(\frac{18}{109}và\frac{5}{30}\)

a) \(\frac{14}{21}+1-|\frac{1}{3}-1|\)

b) \(\frac{1}{3}-|\frac{-1}{4}+\frac{5}{6}|-|\frac{-7}{12}|\)

c)  \(|\frac{-5}{6}+\frac{1}{2}|-\frac{1}{3}+|\frac{-5}{12}|\)

d) \(\frac{-10}{6}-\frac{4}{-8}|\frac{-3}{4}+\frac{5}{-2}|\)

e)  \(|\frac{-5}{2}|-|\frac{-4}{28}+1|-\frac{-3}{14}\)

g)  \(\frac{5}{7}-|\frac{-4}{28}+\frac{1}{2}|-|\frac{-3}{14}|\)

Các bạn giúp mik bài này nhé. Càm ơn nhiều