3/-4+2/7+-1/4+5/7+21/22.66/7
=(-3/4+-1/4)+(2/7+5/7)+9
=-1+1+9
=9
Chúc bạn học tốt!
3/-4+2/7+-1/4+5/7+21/22.66/7
=(-3/4+-1/4)+(2/7+5/7)+9
=-1+1+9
=9
d) \(\dfrac{-3 }{7 } + \dfrac{5 }{ 13 }+ \dfrac{-4 }{ 7}\)
\(e ) \dfrac{-5}{21}+ \dfrac{-2}{21}+\dfrac{-8}{24}\) \(\dfrac{-3 }{7 } + \dfrac{5 }{ 13 }+ \dfrac{-4 }{ 7}\)\( e)\dfrac{-5 }{ 21} + \dfrac{-2 }{21 } + \dfrac{-8 }{ 4}\)
f
\(a,\dfrac{3}{5}+\dfrac{-5}{9}\)
\(b,\dfrac{1}{3}+\dfrac{-4}{3};\dfrac{4}{7}\)
\(c,-\dfrac{27}{23}+\dfrac{5}{21}+\dfrac{4}{23}+\dfrac{16}{21}+\dfrac{1}{2}\)
\(d,\dfrac{-8}{9}+\dfrac{1}{9}.\dfrac{2}{9}+\dfrac{1}{9}.\dfrac{7}{9}\)
\(\dfrac{2}{3}.\dfrac{-5}{7}\)
\(\dfrac{-1}{3}.\dfrac{5}{9}\)
\(\dfrac{-2}{5}.\dfrac{10}{4}\)
\(\dfrac{-3}{7}.\dfrac{5}{15}\)
\(\dfrac{-7}{3}.\dfrac{9}{21}\)
a ) \(\dfrac{7}{-25}\) + \(\dfrac{-8}{25}\)
b ) \(\dfrac{7}{21}\) - \(\dfrac{9}{-36}\)
c )\(\dfrac{-3}{4}\) + \(\dfrac{2}{7}\) + \(\dfrac{1}{4}\)+\(\dfrac{5}{7}\)
Tính hợp lý:
\(a.\dfrac{-3}{5}+\dfrac{7}{21}+\dfrac{-4}{5}+\dfrac{7}{5}\) \(b.\dfrac{-3}{17}+\left(\dfrac{2}{3}+\dfrac{3}{17}\right)\)
\(c.\dfrac{-5}{21}+\left(\dfrac{-16}{21}+1\right)\)
a , cho A = \(\dfrac{1}{1^2}+\dfrac{1}{2^2}+\dfrac{1}{3^2}+\dfrac{1}{4^2}+...+\dfrac{1}{99^2}\) . Chứng minh A < \(\dfrac{7}{4}\)
b ,cho B = 21 + 22 + 23 + ... + 260 . Chứng minh B \(⋮\) 21
Bài 4: So sánh:
a. \(\dfrac{2}{3}\)và\(\dfrac{1}{4}\)
b. \(\dfrac{7}{10}\)và\(\dfrac{7}{8}\)
c. \(\dfrac{6}{7}\)và\(\dfrac{3}{5}\)
d. \(\dfrac{14}{21}\)và\(\dfrac{60}{72}\)
\(\left(\dfrac{2}{3}-\dfrac{1}{2}-\dfrac{1}{3}\right).\left(1-\dfrac{1}{4}-\dfrac{1}{7}\right)\)
\(\left(\dfrac{15}{21}:\dfrac{5}{7}\right):\left(\dfrac{6}{5}:2\right)\)
5. \(\dfrac{-3}{7}\) + \(\dfrac{5}{13}\) + \(\dfrac{-4}{12}\)
6. \(\dfrac{-5}{21}\) + \(\dfrac{-2}{21}\) + \(\dfrac{8}{24}\)
7. \(\dfrac{5}{13}\) + \(\dfrac{-5}{7}\) + \(\dfrac{-20}{41}\) + \(\dfrac{8}{13}\) + \(\dfrac{-21}{41}\)
Giúp tớ với ạ🥺👉🏻👈🏻 Tớ cảm ơn nhiều🥰
