tính nhanh \(\frac{1}{21}\)+\(\frac{2}{21}\)+\(\frac{3}{21}\)+\(\frac{4}{21}\)\(\frac{5}{21}\)+.....\(\frac{18}{21}\)+\(\frac{19}{21}\)+\(\frac{20}{21}\)
Những câu hỏi liên quan
\(ChoM=\frac{18}{18+19+20}+\frac{19}{18+19+21}+\frac{20}{18+19+21}+\frac{21}{18+19+21}.\)
Chứng tỏ rằng 1<M<2
Có \(\frac{18}{18+19+20}>\frac{18}{18+19+20+21}\)
\(\frac{19}{18+19+21}>\frac{19}{18+19+20+21}\)
\(\frac{20}{18+19+21}>\frac{20}{18+19+20+21}\)
\(\frac{21}{18+19+21}>\frac{21}{18+19+20+21}\)
=> \(\frac{18}{18+19+20}+\frac{19}{18+19+21}+\frac{20}{18+19+21}+\frac{21}{18+19+21}>\frac{18}{18+19+20+21}+\frac{19}{18+19+20+21}+\frac{20}{18+19+20+21}+\frac{21}{18+19+20+21}\)
=> \(\frac{18}{18+19+20}+\frac{19}{18+19+21}+\frac{20}{18+19+21}+\frac{21}{18+19+21}>\frac{18+19+20+21}{18+19+20+21}\)
=>\(\frac{18}{18+19+20}+\frac{19}{18+19+21}+\frac{20}{18+19+21}+\frac{21}{18+19+21}>1\)
=>M>1
Còn lại mình không biết, đúng thì tick nha
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\(\left(1\frac{75}{100}+\frac{18}{21}+\frac{19}{32}+\frac{1}{4}+\frac{3}{21}+\frac{13}{21}\right):5\)
TÍNH :
\(A=\frac{\frac{5}{18}+\frac{6}{19}+\frac{7}{20}+\frac{8}{21}+....+\frac{21}{34}-17}{\frac{1}{1.2}+\frac{1}{3.4}+\frac{1}{5.6}+....+\frac{1}{33.34}}\)
a,left(9,75.21frac{3}{7}+frac{39}{4}.18frac{4}{7}right).frac{15}{78}
b,frac{-7}{21}+left(1+frac{1}{3}right) c,frac{2}{15}+left(frac{5}{9}+frac{-6}{9}right)
d,left(frac{-1}{5}+frac{3}{12}right)+frac{-3}{4}
e,frac{4}{20}+frac{16}{42}+frac{6}{15}+frac{-3}{5}+frac{2}{21}+frac{-10}{21}+frac{3}{20}
Đọc tiếp
\(a,\left(9,75.21\frac{3}{7}+\frac{39}{4}.18\frac{4}{7}\right).\frac{15}{78}\)
\(b,\frac{-7}{21}+\left(1+\frac{1}{3}\right)\) \(c,\frac{2}{15}+\left(\frac{5}{9}+\frac{-6}{9}\right)\)
\(d,\left(\frac{-1}{5}+\frac{3}{12}\right)+\frac{-3}{4}\)
\(e,\frac{4}{20}+\frac{16}{42}+\frac{6}{15}+\frac{-3}{5}+\frac{2}{21}+\frac{-10}{21}+\frac{3}{20}\)
tính theo cách nhanh nhất:
\(\frac{4}{20}+\frac{16}{42}+\frac{6}{15}-\frac{3}{5}+\frac{2}{21}-\frac{10}{21}+\frac{3}{20}\)
\(\frac{42}{46}+\frac{250}{186}-\frac{2121}{2323}-\frac{125125}{143143}\)
tính
\(\frac{-20}{21}.\frac{22}{35}+\frac{-20}{21}.\frac{13}{35}+\frac{-22}{21}\)
=\(\frac{-20}{21}.\left(\frac{22}{35}+\frac{13}{35}\right)+\frac{-22}{21}\)
=\(\frac{-20}{21}.\left(\frac{35}{35}\right)+\frac{-22}{21}\)
=\(\frac{-20}{21}+\frac{-22}{21}\)
=\(\frac{-42}{21}\)=-2
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a.\(\frac{27}{12}+\frac{5}{21}-\frac{4}{23}+\frac{6}{21}+\frac{1}{2}\)
b.\(\frac{1}{2}+(-\frac{1}{7})-(\frac{-1}{13})+\frac{-1}{3}-(\frac{-2}{5})+\frac{-11}{21}+\frac{1}{10}\)
\(\frac{-5}{21}+\frac{-2}{21}+\frac{1}{4}\)
\(\dfrac{-5}{21}+\dfrac{-2}{21}+\dfrac{1}{4}=\dfrac{-7}{21}+\dfrac{1}{4}=\dfrac{-1}{3}+\dfrac{1}{4}=\dfrac{-1}{12}\)
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a)\(\frac{16}{21}+\frac{4}{23}+\frac{5}{21}-\frac{4}{23}-\frac{5}{21}\)
b)\(\left(\frac{3}{4}\right)^3:\left(\frac{3}{4}\right)^2\)
c)\(\frac{1}{3}.\frac{-4}{5}+\frac{1}{3}.\frac{-6}{5}\)
\(a.=\frac{16}{21}+\left(\frac{5}{21}-\frac{5}{21}\right)+\left(\frac{4}{23}-\frac{4}{23}\right).\)
\(=\frac{16}{21}+0+0=\frac{16}{21}\)
\(b.=\left(\frac{3}{4}\right)^{3-2}=\left(\frac{3}{4}\right)^1=\frac{3}{4}\)
\(c.=\frac{1}{3}.\left(\frac{-4}{5}+\frac{-6}{5}\right)\)
\(=\frac{1}{3}.\left(-2\right)=\frac{-2}{3}\)
Nhớ k cho mình nhé! Thank you!!!
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