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Tính:
a, 9-9x9+9-9
= 9 - 81 + 9 - 9
= - 72 + 0
= -72
b, 10-10x10x10
= 10 - 10 x 100
= 10 - 1000
= -990
c, 11+11:11+11
= 11 + 1 + 11
= 12 + 11
= 23
d, 12x12:12:12
= 144 : 1
= 144
![](https://rs.olm.vn/images/avt/0.png?1311)
a)\(3\frac{4}{10}>2\frac{9}{10}\)
b)\(3\frac{4}{10}< 3\frac{9}{10}\)
c)\(5\frac{1}{10}>2\frac{9}{10}\)
d)\(3\frac{4}{10}=3\frac{2}{5}\)
Hok tốt!~
![](https://rs.olm.vn/images/avt/0.png?1311)
a). 3 9/10 > 2 9/10
b).3 4/10 < 3 9/10
c).5 1/10 > 2 9/10
d).3 4/10 = 3 2/5
![](https://rs.olm.vn/images/avt/0.png?1311)
a) \(\dfrac{5}{7}\times\dfrac{5}{9}+\dfrac{4}{9}\times\dfrac{5}{7}\)
\(=\dfrac{5}{7}\times\left(\dfrac{4}{9}+\dfrac{5}{9}\right)\)
\(=\dfrac{5}{7}\times1\)
\(=\dfrac{5}{7}\)
b) \(\dfrac{1}{10}+\dfrac{5}{9}+\dfrac{4}{9}+\dfrac{9}{10}-1\)
\(=\left(\dfrac{5}{9}+\dfrac{4}{9}\right)+\left(\dfrac{1}{10}+\dfrac{9}{10}-1\right)\)
\(=1+0\)
\(=1\)
c) \(\dfrac{5}{7}\times\dfrac{5}{9}+\dfrac{4}{9}\times\dfrac{5}{7}+\dfrac{2}{7}\)
\(=\dfrac{5}{7}\times\left(\dfrac{5}{9}+\dfrac{4}{9}\right)+\dfrac{2}{7}\)
\(=\dfrac{5}{7}+\dfrac{2}{7}\)
\(=1\)
d) \(\dfrac{2}{7}+\dfrac{2}{8}+\dfrac{1}{4}+\dfrac{1}{7}+\dfrac{4}{7}\)
\(=\left(\dfrac{2}{8}+\dfrac{1}{4}\right)+\left(\dfrac{2}{7}+\dfrac{1}{7}+\dfrac{4}{7}\right)\)
\(=\left(\dfrac{1}{4}+\dfrac{1}{4}\right)+1\)
\(=\dfrac{1}{2}+1\)
\(=\dfrac{3}{2}\)
e) \(\dfrac{4}{5}+\dfrac{3}{10}+\dfrac{2}{10}+0,7\)
\(=\dfrac{4}{5}+\dfrac{5}{10}+\dfrac{7}{10}\)
\(=\dfrac{4}{5}+\dfrac{12}{10}\)
\(=\dfrac{4}{5}+\dfrac{6}{5}\)
\(=\dfrac{10}{5}\)
\(=2\)
g) \(362\times728+326\times272\)
\(=326\times\left(728+272\right)\)
\(=326\times1000\)
\(=326000\)
![](https://rs.olm.vn/images/avt/0.png?1311)
\(A=\frac{10}{5.7}+\frac{10}{7.9}+\frac{10}{9.11}+...+\frac{10}{33.35}\)
\(\Rightarrow A=10.\left(\frac{1}{5.7}+\frac{1}{7.9}+\frac{1}{9.11}+...+\frac{1}{33.35}\right)\)
Đặt \(B=\frac{1}{5.7}+\frac{1}{7.9}+\frac{1}{9.11}+...+\frac{1}{33.35}\)
\(\Rightarrow2B=\frac{2}{5.7}+\frac{2}{7.9}+\frac{2}{9.11}+...+\frac{2}{33.35}\)
\(\Rightarrow2B=\frac{1}{5}-\frac{1}{35}=\frac{6}{35}\)
\(\Rightarrow B=\frac{3}{35}\)
\(\Rightarrow A=10.\frac{3}{35}=\frac{30}{35}=\frac{6}{7}\)
_Học tốt_
![](https://rs.olm.vn/images/avt/0.png?1311)
\(\frac{1}{10}+\frac{9}{10}+\frac{10}{10}+9+\frac{160}{2}\)
\(=\frac{10}{10}+\frac{10}{10}+9+\frac{160}{2}\)
\(=1+1+9+80\)
\(=91\)
Ta có \(\frac{1}{10}+\frac{9}{10}+\frac{10}{10}+9+\frac{160}{2}=\left(\frac{1}{10}+\frac{9}{10}\right)+\left(\frac{10}{10}+9\right)+\frac{160}{2}\)
\(=1+10+80\)
\(=91\)
Vậy giá trị biểu thức là 91
![](https://rs.olm.vn/images/avt/0.png?1311)
9 : 10 = 0.9 nka
9 : 10 = 0,9