Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
\(\frac{11}{9}+\frac{35}{18}\)
\(=\frac{19}{6}\)
\(\frac{22}{21}:\frac{1}{2}+\frac{25}{12}:\frac{1}{2}\)
\(\frac{44}{21}+\frac{25}{6}\)
\(\frac{263}{42}\)
a,Đặt \(A=\frac{1}{1\times4}+\frac{1}{4\times7}+...+\frac{1}{97\times100}\)
\(\Rightarrow3A=\frac{3}{1\times4}+\frac{3}{4\times7}+...+\frac{3}{97\times100}\)
\(\Rightarrow3A=\frac{1}{1}-\frac{1}{4}+\frac{1}{4}-\frac{1}{7}+...+\frac{1}{97}-\frac{1}{100}\)
\(\Rightarrow3A=1-\frac{1}{100}=\frac{99}{100}\)
\(\Rightarrow A=\frac{99}{300}\)
b, \(\frac{1}{2}\times\frac{2}{3}\times...\times\frac{99}{100}=\frac{1\times2\times...\times99}{2\times3\times...\times1000}=\frac{1}{100}\)
c, \(\frac{3}{4}\times\frac{8}{9}\times...\times\frac{99}{100}=\frac{1.3}{2.2}\times\frac{2.4}{3.3}\times...\times\frac{9.11}{10.10}=\frac{1.2.....9}{2.3.....10}\times\frac{3.4.....11}{2.3.....10}=\frac{1}{10}\times\frac{11}{2}=\frac{11}{20}\) (dấu . là dấu nhân)
Mình ghi nhầm đó, lẽ ra phải thế này cơ:\(\left(30:7\frac{1}{2}+0,5x3-1,5\right)x\left(4\frac{1}{2}-\frac{9}{2}\right):\left(14,5x100\right)\)
\((30:7\frac{1}{2}\)\(+0,5x3\)\(-1,5)x(4\frac{1}{2}\)\(-\frac{9}{2}\)\():(14,5x100)\)
\(=\)\((30:7\frac{1}{2}\)\(+0,5x3\) \(-1,5)x(\frac{9}{2}\)\(-\frac{9}{2}\)\()\)\(:(14,5x100)\)
\(=30:7\frac{1}{2}\)\(+0,5x3-1,5)x0x(14,5x100)\)
\(=0\)
Chúc bạn học tốt!
mik nhầm nha mn
\(1-\left\{5\frac{4}{9}+x-7\frac{7}{18}\right\}:15\frac{3}{4}=0\)
\(\left(a\right)37064-64\left(82+\frac{42966}{217}\right)\)
\(=37064-64\left(82+198\right)\)
\(=37064-64\cdot280\)
\(=30764-17920=19144\)
\(\left(b\right)320-\left(120,5+95,25+5,25\right)+\frac{84}{12}\cdot12,5\)
\(=320-\left(120,5+100,5\right)+7\cdot12,5\)
\(=320-221+87,5=11,5\)
\(\left(c\right)\left(4\frac{2}{5}+2\frac{3}{7}\right)-\left(2\frac{2}{5}-5\frac{4}{7}\right)\)
\(=4\frac{2}{5}-2\frac{2}{5}+2\frac{3}{7}+5\frac{4}{7}\)
\(=2+8=10\)
\(\left(d\right)\left(\frac{1998}{18}-\frac{1443}{13}\right)\left(16996-\frac{1110}{30}\cdot305\right)\)
\(=\left(111-111\right)\left(16996-\frac{1110}{30}\cdot305\right)\)
\(=0\left(16996-\frac{1110}{30}\cdot305\right)=0\)
\(\left(e\right)5\frac{3}{5}+1,75+6\frac{1}{8}+4\frac{1}{4}+3,875+3,4\)
\(=5\frac{3}{5}+1\frac{3}{4}+6\frac{1}{8}+4\frac{1}{4}+3\frac{7}{8}+3\frac{2}{5}\)
\(=5\frac{3}{5}+3\frac{2}{5}+1\frac{3}{4}+4\frac{1}{4}+6\frac{1}{8}+3\frac{7}{8}\)
\(=9+6+10=25\)
\(\frac{22}{21}\): ( \(\frac{63}{4}\)\(-\frac{61}{4}\)) \(+\) \(\frac{25}{12}\): ( \(\frac{31}{4}\)\(-\)\(\frac{29}{4}\))
= \(\frac{22}{21}\): \(\frac{1}{2}\)+ \(\frac{25}{12}\): \(\frac{1}{2}\)
= ( \(\frac{22}{21}\)+ \(\frac{25}{12}\) ) : \(\frac{1}{2}\)
= \(\frac{263}{84}\) : \(\frac{1}{2}\)
=\(\frac{263}{42}\)
\(1\frac{1}{21}:\left(15,75-15\frac{1}{4}\right)+2\frac{1}{12}:\left(7\frac{3}{4}-7,25\right)\)
=\(\frac{22}{21}:\left(\frac{63}{4}-\frac{61}{4}\right)+\frac{25}{12}:\left(\frac{31}{4}-\frac{29}{4}\right)\)
=\(\frac{22}{21}:\frac{1}{2}+\frac{25}{12}:\frac{1}{2}=\frac{22x2}{21}+\frac{25x2}{12}\)
=\(\frac{44}{21}+\frac{25}{6}=\frac{88+175}{42}=\frac{263}{42}\)