\(21\dfrac{1}{5}|\dfrac{6}{ }\) 21 và 1 phần 5 chia 6 nhé
\(\dfrac{-5}{21}+(\dfrac{-16}{21}+1)\)
\(\dfrac{-3}{8}.\dfrac{1}{6}+\dfrac{3}{-8}.\dfrac{5}{6}+\dfrac{-10}{16}\)
a)
\(\dfrac{-5}{21}+\left(\dfrac{-16}{21}+1\right)=\dfrac{-5}{21}+\dfrac{-16}{21}+1\)=\(-1+1=0\)
`(-5)/21+((-16)/21+1)`
`=(-5)/21-16/21+1`
`=-1+1=0`
`(-3)/8*1/6+3/(-8)*5/6+(-1)/16`
`=-3/8*(1/6+5/6)-10/16`
`=-3/8-10/16`
`=-6/16-10/16=-16/16=-1`
\(\dfrac{-3}{8}.\dfrac{1}{6}+\dfrac{-3}{8}.\dfrac{5}{6}+\dfrac{-10}{16}\)
=\(\dfrac{-3}{8}.\left(\dfrac{1}{6}+\dfrac{5}{6}\right)+\dfrac{-10}{16}\)
=\(\dfrac{-3}{8}+\dfrac{-5}{8}=-1\)=
Tính rồi rút gọn:
a) \(\dfrac{2}{9}+\dfrac{1}{9}\) b) \(\dfrac{5}{6}+\dfrac{1}{6}\) c) \(\dfrac{11}{8}-\dfrac{5}{8}\) d) \(\dfrac{5}{21}-\dfrac{2}{21}\)
6. ÉT O ÉT
\(\dfrac{9}{7}\) và \(\dfrac{5}{6}\) \(\dfrac{4}{7}\) và \(\dfrac{8}{21}\) \(\dfrac{2}{5};\dfrac{1}{3}\) và \(\dfrac{1}{2}\) \(\dfrac{1}{3};\dfrac{4}{3}\) và\(\dfrac{1}{5}\)
a: 9/7>1>5/6
b: 4/7=12/21>8/21
c: 2/5=12/30
1/3=10/30
1/2=15/30
mà 10<12<15
nên 1/3<2/5<1/2
P=\(\left(\dfrac{1}{5}+\dfrac{1}{21}-\dfrac{1}{2015}\right):\left(\dfrac{1}{21}+\dfrac{1}{5}-\dfrac{1}{2015}+\dfrac{1}{5}.\dfrac{2}{21}.\dfrac{3}{2015}\right)+6:\left(26.2015-99\right)\)
P=\(\left(\dfrac{1}{5}+\dfrac{1}{21}-\dfrac{1}{2015}\right):\left(\dfrac{1}{21}+\dfrac{1}{5}-\dfrac{1}{2015}+\dfrac{1}{5}.\dfrac{2}{21}.\dfrac{3}{2015}\right)+6:\left(26.2015-99\right)\)
\(\dfrac{5}{7}-x=\dfrac{9}{21}\)
\(-x-\dfrac{1}{3}=\dfrac{2}{6}\)
\(\dfrac{-5}{6}-x=\dfrac{7}{12}+\dfrac{-1}{3}\)
\(\dfrac{5}{7}-x=\dfrac{9}{21}\\ \Rightarrow\dfrac{5}{7}-x=\dfrac{3}{7}\\ \Rightarrow x=\dfrac{5}{7}-\dfrac{3}{7}\\ \Rightarrow x=\dfrac{2}{7}\\ b,-x-\dfrac{1}{3}=\dfrac{2}{6}\\ \Rightarrow-x=\dfrac{2}{6}+\dfrac{1}{3}\\ \Rightarrow-x=\dfrac{2}{3}\\ \Rightarrow x=-\dfrac{2}{3}\\ \dfrac{-5}{6}-x=\dfrac{7}{12}+\dfrac{-1}{3}\\ \Rightarrow\dfrac{-5}{6}-x=\dfrac{1}{4}\\ \Rightarrow x=\dfrac{-5}{6}-\dfrac{1}{4}\\ \Rightarrow x=-\dfrac{13}{12}\)
Tính.
a)\(N=\dfrac{6:\dfrac{3}{5}-1\dfrac{1}{6}.\dfrac{6}{7}}{\dfrac{1}{5}.\dfrac{10}{11}+5\dfrac{2}{11}}\)
b)Tính nhanh:
\(K=\dfrac{75}{100}+\dfrac{18}{21}+\dfrac{19}{32}+\dfrac{1}{4}+\dfrac{3}{21}+\dfrac{13}{32}\)
b, \(K =\) \(\dfrac{75}{100}+\dfrac{18}{21}+\dfrac{19}{32}+\dfrac{1}{4}+\dfrac{3}{21}+\dfrac{13}{32}\)
\(K = \) \(\dfrac{3}{4}+\dfrac{18}{21}+\dfrac{19}{32}+\dfrac{1}{4}+\dfrac{3}{21}+\dfrac{13}{32}\)
\(K = \) \(\left(\dfrac{3}{4}+\dfrac{1}{4}\right)+\left(\dfrac{18}{21}+\dfrac{3}{21}\right)+\left(\dfrac{19}{32}+\dfrac{13}{32}\right)\)
\(K = \) \(1 + 1 + 1\)
\(K = \) \(3\)
a) \(\dfrac{5}{11}\) + \(\dfrac{7}{16}\) x \(\dfrac{8}{21}\) =
b) \(\dfrac{5}{2}\) - \(\dfrac{8}{5}\) : 6 =
Mọi người trình bày nhé
\(\dfrac{41}{66}\)
\(\dfrac{67}{30}\)
Tính giá trị biểu thức:
D=\(\left(\dfrac{136}{15}-\dfrac{28}{5}+\dfrac{62}{10}\right).\dfrac{21}{24}\)
F= \(\dfrac{5}{6}+6\dfrac{5}{6}.\left(11\dfrac{5}{20}-9\dfrac{1}{4}\right):8\dfrac{1}{3}\)
\(F=\dfrac{5}{6}+6\dfrac{5}{6}\left(11\dfrac{5}{20}-9\dfrac{1}{4}\right):8\dfrac{1}{3}\)
\(F=\dfrac{5}{6}+\dfrac{41}{6}\left(\dfrac{225}{20}-\dfrac{37}{4}\right):\dfrac{25}{3}\)
\(F=\dfrac{5}{6}+\dfrac{41}{6}.2.\dfrac{3}{25}\)
\(F=\dfrac{5}{6}+\dfrac{41}{25}.\dfrac{3}{25}\)
\(F=\dfrac{5}{6}+\dfrac{41}{25}\)
\(F=\dfrac{371}{150}\)
\(D=\left(\dfrac{136}{15}-\dfrac{28}{5}+\dfrac{62}{10}\right)\times\dfrac{21}{24}\)
\(D=\left(\dfrac{272}{30}-\dfrac{168}{30}+\dfrac{186}{30}\right)\times\dfrac{21}{24}\)
\(D=\dfrac{290}{30}\times\dfrac{21}{24}\)
\(D=\dfrac{29}{3}\times\dfrac{7}{8}\)
\(D=\dfrac{203}{24}\)