Câu 1: Tính

a) A=\(\left(\frac{1}{2^2}-1\right).\left(\frac{1}{3^2}-1\right).....\left(\frac{1}{98^2}-1\right).\left(\frac{1}{99^2}-1\right)\)

b) B=\(\frac{1}{2}:\left(-1\frac{1}{2}\right):1\frac{1}{3}:\left(-1\frac{1}{4}\right):1\frac{1}{5}:\left(-1\frac{1}{6}\right):...:\left(-1\frac{1}{100}\right)\)

c) C=\(\frac{4^6.9^5+6^9.120}{-8^4.3^{12}+6^4}\)

A=\(\left(1-\frac{1}{4}\right)\left(1-\frac{1}{9}\right)\left(1-\frac{1}{16}\right).....\left(1-\frac{1}{100}\right)\)

B=\(\left(1+\frac{1}{3}\right)\left(1+\frac{1}{8}\right)+\left(1+\frac{1}{15}\right)......\left(1+\frac{1}{100}\right)\)

D=\(\frac{8}{9}.\frac{15}{16}.\frac{24}{25}.....\frac{2499}{2500}\)

a)\(\left(1\frac{1}{3}\right)\left(1\frac{1}{8}\right)\left(1\frac{1}{15}\right)...\left(1\frac{1}{99}\right)\)

b)\(\left(1+\frac{1}{3}\right)\left(1+\frac{1}{8}\right)\left(1+\frac{1}{15}\right)\left(1+\frac{1}{24}\right)\left(1+\frac{1}{99}\right)\)

Bài 1:

\(\frac{32}{15}:\left(-1\frac{1}{5}+1\frac{1}{3}\right)\) \(1\frac{13}{15}.0,75-\left(\frac{8}{15}+0.25\right).\frac{24}{47}\)

\(0,2.\frac{15}{36}-\left(\frac{2}{5}+\frac{2}{3}\right):1\frac{1}{5}\) \(5:\left(4\frac{25}{28}-1\frac{25}{28}\right)-1\frac{3}{8}:\left(\frac{3}{8}+\frac{9}{20}\right)\)

Câu 1: Tính

a) A=\(\left(\frac{1}{2^2}-1\right).\left(\frac{1}{3^2}-1\right).....\left(\frac{1}{98^2}-1\right).\left(\frac{1}{99^2}-1\right)\)

b) B=\(\frac{1}{2}:\left(-1\frac{1}{2}\right):1\frac{1}{3}:\left(-1\frac{1}{4}\right):1\frac{1}{5}:\left(-1\frac{1}{6}\right):...:\left(-1\frac{1}{100}\right)\)

c) C=\(\frac{4^6.9^5+6^9.120}{-8^4.3^{12}+6^4}\)

Tìm x

\(\frac{5}{2}-\left(\frac{3}{2}-2\frac{1}{3}+x\right)=\frac{8}{15}-\left(\frac{1}{4}-\frac{7}{10}\right)\)

\(1\frac{2}{3}-1\frac{3}{5}+x=\frac{2}{5}-\left|\frac{3}{4}-\frac{7}{8}\right|\)

\(2-\left(\frac{2}{3}-3\frac{1}{4}+x\right)=1\left|\frac{1}{6}-\frac{13}{12}\right|\)

số số hạng của dãy\(\frac{1}{3.6};\frac{1}{6.9};\frac{1}{9.12};...;\frac{1}{156.159}\)là