Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
\(a,\frac{2001}{2002}.\frac{5}{7}.\frac{2002}{5}.\frac{7}{2001}=\left(\frac{2001}{2002}.\frac{7}{2001}\right).\left(\frac{5}{7}.\frac{2002}{5}\right)\)
\(=\frac{7}{2002}.\frac{2002}{7}=1\)
\(b,\frac{5}{7}.\frac{7}{9}.\frac{9}{11}.\frac{11}{13}=\left(\frac{5}{7}.\frac{7}{9}\right).\left(\frac{9}{11}.\frac{11}{13}\right)=\frac{5}{9}.\frac{9}{13}\)
\(=\frac{5}{13}\)
\(\frac{9}{11}\)< \(\frac{13}{15}\)
\(\frac{19}{15}\)< \(\frac{15}{11}\)
\(1,\frac{3}{5}+\frac{7}{2}-\frac{4}{7}=\frac{42}{70}+\frac{245}{70}-\frac{40}{70}=\frac{247}{70}\)
\(2,\frac{4}{5}-\frac{1}{3}+\frac{3}{4}=\frac{48}{60}-\frac{20}{60}+\frac{45}{60}=\frac{73}{60}\)
\(3,\frac{1}{3}\times\frac{5}{7}:\frac{7}{2}=\frac{5}{21}:\frac{7}{2}=\frac{10}{147}\)
\(4,\frac{1}{2}:\frac{2}{7}\times\frac{4}{7}=\frac{7}{4}\times\frac{4}{7}=1\)
\(5,\frac{19}{15}\times\frac{3}{7}:\frac{4}{9}=\frac{19}{35}:\frac{4}{9}=\frac{171}{140}\)
\(6,\frac{11}{3}:\frac{9}{16}:\frac{3}{8}=\frac{176}{27}:\frac{3}{8}=\frac{1408}{81}\)
_Chúc bạn học tốt _
bài 1
a) 5x24x36/6x12x10
=5x12x2x6x6/6x12x5x2
=6
b)1/3x5/7+3/9x2/7
=1/3x5/7+1/3*2/7
=1/3x(5/7+2/7)
=1/3x(7/7)
=1/3x1
=1/3
k nha
Tính
\(\frac{15}{25}+\frac{80}{125}+\frac{12}{42}+\frac{78}{100}+\frac{18}{12}\)
\(\frac{3}{5}+\frac{16}{25}+\frac{6}{21}+\frac{39}{50}+\frac{3}{2}\)
\(\frac{15}{25}+\frac{16}{25}+\frac{39}{50}+\frac{6}{21}+\frac{3}{2}\)
\(\frac{62}{50}+\frac{39}{50}+\frac{12}{42}+\frac{63}{42}\)
\(\frac{101}{50}+\frac{75}{42}\)
\(\frac{4242}{2100}+\frac{3750}{2100}\)
\(\frac{7992}{2100}\)
1/4*5+1/5*6+1/6*7+1/7*8=1/4-1/5+1/5-1/6+1/6-1/7+1/7-1/8
=1/4-1/8
1/8
a, \(\frac{5}{11}\times\frac{7}{25}+\frac{15}{11}\times\frac{1}{5}\)
\(=\frac{5}{11}\times\frac{7}{25}+\frac{5}{11}\times\frac{3}{5}\)
\(=\frac{5}{11}\times\left(\frac{7}{25}+\frac{3}{5}\right)\)
\(=\frac{5}{11}\times\frac{22}{25}\)
\(=\frac{2}{5}\)
b, \(\frac{3}{7}\times\frac{25}{19}-\frac{1}{7}\times\frac{18}{19}\)
\(=\frac{1}{7}\times\frac{75}{19}-\frac{1}{7}\times\frac{18}{19}\)
\(=\frac{1}{7}\times\left(\frac{75}{19}-\frac{18}{19}\right)\)
\(=\frac{1}{7}\times3\)
\(=\frac{3}{7}\)
\(\frac{18}{15}-\frac{85}{100}+\frac{42}{10}+\frac{18}{9}-\frac{12}{16}\)
= \(\frac{7}{20}+\frac{42}{10}+\frac{18}{9}-\frac{12}{16}\)
= \(\frac{23}{20}+\frac{18}{9}-\frac{12}{16}\)
= \(\frac{63}{20}-\frac{12}{16}\)
= \(\frac{12}{5}\).
\(\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+...+\frac{1}{56}=\frac{1}{2x3}+\frac{1}{3x4}+\frac{1}{4x5}...\frac{1}{7x8}=\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{7}-\frac{1}{8}\)\(-\frac{1}{8}=\frac{1}{2}-\frac{1}{8}=\frac{3}{8}\)
b,
Ta có: \(1-\frac56+\frac{7}{12}-\frac{9}{20}+\frac{11}{30}-\frac{13}{42}+\frac{15}{56}\)
\(=1-\frac{2+3}{2\times3}+\frac{3+4}{3\times4}-\frac{4+5}{4\times5}+\frac{5+6}{5\times6}-\frac{6+7}{6\times7}+\frac{7+8}{7\times8}\)
\(=1-\frac12-\frac13+\frac13+\frac14-\frac14-\frac15+\frac15+\frac16-\frac16-\frac17+\frac17+\frac18\)
\(=1+\frac18=\frac98\)