NT
1
K
Khách
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NB
0
NT
1
18 tháng 1 2018
\(\left(\frac{3}{4}+\frac{2}{11}-\frac{8}{13}\right)+\left(\frac{1}{4}-\frac{5}{13}\right)\)
\(=\frac{3}{4}+\frac{2}{11}-\frac{8}{13}+\frac{1}{4}-\frac{5}{13}\)
\(=\left(\frac{3}{4}+\frac{1}{4}\right)+\frac{2}{11}-\left(\frac{8}{13}+\frac{5}{13}\right)\)
\(=1+\frac{2}{11}-1\)
\(=\frac{2}{11}\)
\(\left(\frac{9}{53}+\frac{21}{31}\right)+\left(\frac{44}{53}-\frac{16}{7}\right)+\frac{10}{31}\)
\(=\frac{9}{53}+\frac{21}{31}+\frac{44}{53}-\frac{16}{7}+\frac{10}{31}\)
\(=\left(\frac{9}{53}+\frac{44}{53}\right)+\left(\frac{21}{31}+\frac{10}{31}\right)-\frac{16}{7}\)
\(=1+1-\frac{16}{7}\)
\(=2-\frac{16}{7}\)
\(=\frac{14}{7}-\frac{16}{7}\)
\(=\frac{-2}{7}\)
DQ
0
NN
1
5 tháng 5 2018
\(\left(\frac{21}{31}+\frac{2013}{6039}\right)-\left(\frac{44}{53}-\frac{10}{31}\right)-\frac{9}{53}\)
\(=\frac{21}{31}+\frac{1}{3}-\frac{44}{53}+\frac{10}{31}-\frac{9}{53}\)
\(=\left(\frac{21}{31}+\frac{10}{31}\right)+\left(\frac{-44}{53}-\frac{9}{53}\right)+\frac{1}{3}\)
\(=1+\left(-1\right)+\frac{1}{3}\)
\(=\frac{1}{3}\)
VN
1 tháng 7 2018
a, -3/4 + 3/7 + -1/4 + 4/9 + 4/7
=\(\left(\frac{-3}{4}+\frac{-1}{4}\right)+\left(\frac{3}{7}+\frac{4}{7}\right)+\frac{4}{9}\)
=\(-1+1+\frac{4}{9}\)
=\(\frac{4}{9}\)
b, -7/9 x 4/11 + -7/9 x 7/11 + 5 và 7/9
\(=\frac{7}{9}x\frac{-4}{11}+\frac{7}{9}x\frac{-7}{11}+5x\frac{7}{9}\)
\(=\frac{7}{9}x\left(\frac{-4}{11}+\frac{-7}{11}+5\right)\)
\(=\frac{7}{9}x4\)
\(=\frac{28}{9}\)
c, ( 21/31 + 2013/6039 ) - ( 44/53 - 10/31) - /53
25 tháng 1 2019
\(A=\frac{21}{31}+\frac{-16}{7}+\frac{44}{53}+\frac{10}{21}+\frac{9}{53} \)
\(A=\left(\frac{16}{7}+\frac{10}{21}\right)+\left(\frac{44}{53}+\frac{9}{53}\right)+\frac{21}{31}\)
\(A=\frac{58}{21}+1+\frac{21}{31}\)
\(A=\frac{100}{21}\)
\(B=6\left(\frac{1}{15.18}+\frac{1}{18.21}+...+\frac{1}{87.90}\right)\)
\(B=6\left(\frac{1}{15}-\frac{1}{18}+\frac{1}{18}-\frac{1}{21}+...+\frac{1}{87}-\frac{1}{90}\right)\)
\(B=6\left(\frac{1}{15}-\frac{1}{90}\right)\)
\(B=6.\frac{1}{18}\)
\(B=\frac{1}{3}\)
15 tháng 3 2019
\(\frac{42}{46}\)\(+\frac{250}{286}+\frac{-125125}{143143}\)
\(=\frac{21}{23}+\frac{125}{143}+\frac{-125}{143}\)
\(=\frac{21}{23}+\left(\frac{125}{143}+\frac{-125}{143}\right)\)
\(=\frac{21}{23}+0\)
\(=\frac{21}{23}\)
k cho mik nha✔
15 tháng 3 2019
(\(\frac{21}{31}+\frac{-16}{7}\)) \(+\) (\(\frac{44}{53}+\frac{10}{31}\)) \(+\frac{9}{53}\)
\(=\frac{21}{31}+\frac{-16}{7}+\frac{44}{53}+\frac{10}{31}+\frac{9}{53}\)
\(=\)(\(\frac{21}{31}+\frac{10}{31}\)) \(+\)( \(\frac{44}{53}+\frac{9}{53}\))\(+\frac{-16}{7}\)
\(=1+1+\frac{-16}{7}\)
\(=2\:+\frac{-16}{7}\)
\(=\frac{-2}{7}\)
9 tháng 5 2017
= 21/31 + 1/3 - 44/53 + 10/31 -9/53
= [21/31+10/31] - [44/53 + 9/53] +1/3
= 1-1+1/3 = 1/3
DN
3
WC
8 tháng 6 2016
bỏ ngoặc: 21/31+2013/6039-44/53+10/31-9/53
ta có ; (21/31+10/31)-(44/53+9/53)+1/3
1-1+1/3=1/3
MN
6 tháng 5 2017
(21/31+2013/6039)-(44/53-10/31)-9/53
=21/31+1/3-44/53+10/31-9/53
=(21/31+10/31)-(44/53+9/53)+1/3
=31/31-53/53+1/3
=1-1+1/3
=0+1/3
=1/3!!!
\(\left(\dfrac{21}{31}+\dfrac{-16}{7}\right)+\left(\dfrac{44}{53}+\dfrac{10}{31}\right)+\dfrac{9}{53}.\)
\(\dfrac{21}{31}-\dfrac{16}{7}+\dfrac{44}{53}+\dfrac{10}{31}+\dfrac{9}{53}=\left(\dfrac{21}{31}+\dfrac{10}{31}\right)+\left(\dfrac{44}{53}+\dfrac{9}{53}\right)-\dfrac{16}{7}=1+1-\dfrac{16}{7}=\dfrac{-2}{7}.\)