9187 - x : 409 = 7819

x : 409 = 9187 - 7819

x : 409 = 1368

x = 1368 * 409

x = 559512

dung roi

bạn làm đúng rồi đó!

--------------hok tốt!--------------------

bạn làm đúng nhưng trình bày chưa được

A. = 14/15 * 15/23 * 23/21

     = 14/23 * 23/21

      = 14/21

B. = 1/2 * (9/10 + 8/10 - 7/10)

     = 1/2 * 10/10

      = 1/2 * 1

       = 1/2

a) \(\frac{14}{15}\cdot\frac{23}{21}\cdot\frac{15}{23}=\frac{14}{21}=\frac{2}{3}\)

b)\(\frac{1}{2}\cdot\frac{9}{10}+\frac{1}{2}\cdot\frac{8}{10}-\frac{1}{2}\cdot\frac{7}{10}=\frac{1}{2}\cdot\left(\frac{9}{10}+\frac{8}{10}-\frac{7}{10}\right)=\frac{1}{2}\cdot1=\frac{1}{2}\)

\(25\times32\times125\times15\\=(25\times4)\times(8\times125)\times15\\=100\times1000\times15\\=100000\times15\\=1500000\)

25 x 32 x 125 x 15 

=(125 x 32 ) x (25 x 15 )

= 4000 x 375

=1 500 000

\(25\times32\times125\times15\)

\(=25\times4\times8\times125\times15\)

\(=\left(25\times4\right)\times\left(8\times125\right)\times15\)

\(=100\times1000\times15\)

\(=\left(1000\times15\right)\times100\)

\(=15000\times100=1500000\)

bn phai kb mik mi tra loi

a,2009x867+2009x133=2009x(867+133)=2009x1000=2009000

b,có vẻ sai đề.

Tính giá trị biểu thức sau bằng cách thuân tiện nhất 

a,2009 x 867 + 2009 x 133

= 2009 x ( 867 + 133 )

= 2009 x 1000

= 2009000

b ,2008 x 867 + 2009 x 133

= 2008 × 867 + (2008 + 1) × 133                      

= 2008 × 867 + 2008 × 133 + 133                    

= 2008 × (867 + 133) + 133                               

= 2008 × 1000 + 133                                          

= 2008000 + 133                                              

= 2008133

21 x 25,36 + 25,36 x 80 - 25,36

= 21 x 25,36 + 25,36 x 80 - 25,36 x 1

= 25,36 x ( 21 + 80 - 1 )

= 25,36 x 100

= 2536

/HT\

21 x 25,36 + 25,36 x 80 - 25,36  

=21 x 25,36 + 25,36 x 80 - 25,36 x 1

=25,36 x (21 + 80 -1)

= 25,36 x 100

2536

25,36×21+25,36×80-25,36×1

=25,36×(21+80-1)

=25,36×100

=2536

Ta có:\(\frac{23,26\cdot32\cdot0,6}{0,32\cdot6}\Leftrightarrow\frac{2,326\cdot0,32\cdot6}{0,32\cdot6}=\frac{2,326}{1}=2,326\)

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Mày tự mà làm

Cần gấp thì bằng 202000 nhé! K cho mình

2020x45+2020x54+2020

=2020x45+2020x54+2020x1

=2020x(45+54+1)

=2020x100

=202000

\(\frac{21}{11}.\frac{22}{17}.\frac{68}{63}=\frac{21.22.68}{11.17.63}=\frac{21.11.2.4.17}{11.17.3.21}=\frac{\left(21.11.17\right).\left(2.4\right)}{\left(11.17.21\right).3}=\frac{2.4}{3}=\frac{8}{3}\)

\(\frac{5}{14}.\frac{7}{13}.\frac{26}{25}=\frac{5.7.26}{14.13.25}=\frac{5.7.13.2}{7.2.13.5.5}=\frac{5.7.13.2}{5.7.13.2.5}=\frac{2}{2.5}=\frac{1}{5}\)