Question

TÍNH NHANH

\(A=\frac{1}{12}+\frac{1}{20}+.....+\frac{1}{9900}\)

Answer 1

\(A=\frac{1}{3\cdot4}+\frac{1}{4\cdot5}+...+\frac{1}{99\cdot100}\)

\(A=\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+...+\frac{1}{99}-\frac{1}{100}\)

\(A=\frac{1}{3}-\frac{1}{100}\)

\(A=\frac{97}{300}\)

Answer 2

dễ nhưng mình đang bận , chúc ban học tốt , k mình nha hihi

Answer 3

A = \(\frac{1}{12}+\frac{1}{20}+...+\frac{1}{9900}\)

A = \(\frac{1}{3.4}+\frac{1}{4.5}+...+\frac{1}{99.100}\)

A = 1/3 - 1/4 + 1/4 - 1/5 + ... + 1/99 - 1/100

A = 1/3 - 1/100

A = 97/300

Answer 4

Ta có : 

\(A=\frac{1}{12}+\frac{1}{20}+...+\frac{1}{9900}\)

\(\Rightarrow A=\frac{1}{3.4}+\frac{1}{4.5}+...+\frac{1}{99.100}\)

\(\Rightarrow A=\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+...+\frac{1}{99}-\frac{1}{100}\)

\(\Rightarrow A=\frac{1}{3}-\frac{1}{100}\)

\(\Rightarrow A=\frac{100}{300}-\frac{3}{100}\)

\(\Rightarrow A=\frac{97}{100}\)

~ Ủng hộ nhé 

Answer 5

\(A=\frac{1}{12}+\frac{1}{20}+....+\frac{1}{9900}\)
\(A=\frac{1}{3.4}+\frac{1}{4.5}+....+\frac{1}{99.100}\)
\(A=\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+.....+\frac{1}{99}-\frac{1}{100}\)
\(A=\frac{1}{3}-\frac{1}{100}\)
\(A=\frac{97}{300}\)



 

Answer 6

\(A=\frac{1}{12}+\frac{1}{20}+...+\frac{1}{9900}\)

\(A=\frac{1}{3\cdot4}+\frac{1}{4\cdot5}+...+\frac{1}{99\cdot100}\)

\(A=\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+...+\frac{1}{99}-\frac{1}{100}\)

\(A=\frac{1}{3}-\frac{1}{100}\)

\(A=\frac{100}{300}\)\(-\frac{3}{300}\)

\(A=\frac{97}{300}\)

Answer 7

\(A=\frac{1}{12}+\frac{1}{20}+...+\frac{1}{9900}\)

\(\Rightarrow A=\frac{1}{3.4}+\frac{1}{4.5}+...+\frac{1}{99.100}\)

\(\Rightarrow A=\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+...+\frac{1}{99}-\frac{1}{100}\)

\(\Rightarrow A=\frac{1}{3}-\frac{1}{100}\)

\(\Rightarrow A=\frac{97}{300}\)