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4 tháng 6 2016

\(\frac{5}{12.17}+\frac{3}{34.10}+\frac{7}{60.9}+\frac{9}{27.36}\)

\(=\frac{5}{204}+\frac{3}{340}+\frac{7}{540}+\frac{9}{972}\)

\(=tự.tính.típ.nhé\)

27 tháng 7 2023

a) \(A=27\cdot36+73\cdot99+27\cdot14-49\cdot73\)

\(A=27\cdot\left(36+14\right)+73\cdot\left(99-49\right)\)

\(A=27\cdot50+73\cdot50\)

\(A=50\cdot\left(27+73\right)\)

\(A=50\cdot100\)

\(A=5000\)

b) \(B=\left(4^5\cdot10\cdot5^6+25^5\cdot2^8\right):\left(2^8\cdot5^4+5^7\cdot2^5\right)\)

\(B=\dfrac{\left(2^2\right)^5\cdot2\cdot5\cdot5^6+\left(5^2\right)^5\cdot2^8}{2^8\cdot5^4+5^7\cdot2^5}\)

\(B=\dfrac{2^{11}\cdot5^7+5^{10}\cdot2^8}{2^8\cdot5^4+5^7\cdot2^5}\)

\(B-\dfrac{2^8\cdot5^7\cdot\left(2^3\cdot1+5^3\cdot1\right)}{2^5\cdot5^4\cdot\left(2^3\cdot1+5^3\cdot1\right)}\)

\(B=\dfrac{2^8\cdot5^7}{2^5\cdot5^4}\)

\(B=2^3\cdot5^3\)

\(B=10^3\)

\(B=1000\)

23 tháng 8 2016

60 x 8 + 60 x 6 + 60 x 9 = 60 x ( 8 + 6 + 9 )

                                      = 60 x 23

                                      = 1380

23 tháng 8 2016

=60x(8+6+9)

=60x23

=1380

k đúng cho mk nhe

26 tháng 6 2023

Em cần phần nào nhỉ .

26 tháng 6 2023

A = \(\dfrac{5}{1.6}\)+\(\dfrac{5}{6.11}\)+\(\dfrac{5}{11.16}\)+\(\dfrac{5}{16.21}\)+...+\(\dfrac{5}{101.106}\)

A = \(\dfrac{1}{1}-\dfrac{1}{6}+\dfrac{1}{6}-\dfrac{1}{11}+...+\dfrac{1}{101}-\dfrac{1}{106}\)

A = \(\dfrac{1}{1}\) - \(\dfrac{1}{106}\)

A = \(\dfrac{105}{106}\)

B = \(\dfrac{3}{1.4}\) +\(\dfrac{3}{4.7}\)+\(\dfrac{3}{7.10}\)+...+\(\dfrac{3}{97.100}\)

B = \(\dfrac{1}{1}-\dfrac{1}{4}+\dfrac{1}{4}-\dfrac{1}{7}-\dfrac{1}{10}+...+\dfrac{1}{97}-\dfrac{1}{100}\)

B = \(\dfrac{1}{1}\) - \(\dfrac{1}{100}\)

B = \(\dfrac{99}{100}\)

C = \(\dfrac{1}{2.7}+\dfrac{1}{7.12}\) + \(\dfrac{1}{12.17}\)+...+ \(\dfrac{1}{97.102}\)

C= \(\dfrac{1}{5}\) \(\times\)\(\dfrac{5}{2.7}+\dfrac{5}{7.12}+\dfrac{5}{12.17}+...+\dfrac{5}{97.102}\))

C = \(\dfrac{1}{5}\)\(\times\)(\(\dfrac{1}{2}\) - \(\dfrac{1}{7}\) + \(\dfrac{1}{7}\) - \(\dfrac{1}{12}\) + \(\dfrac{1}{12}\) - \(\dfrac{1}{17}\)+...+ \(\dfrac{1}{97}\) - \(\dfrac{1}{102}\))

C = \(\dfrac{1}{5}\) \(\times\)\(\dfrac{1}{2}\) - \(\dfrac{1}{102}\))

C = \(\dfrac{1}{5}\) \(\times\) \(\dfrac{25}{51}\)

C = \(\dfrac{5}{51}\) 

D = \(\dfrac{1}{2}\) +   \(\dfrac{1}{6}\) + \(\dfrac{1}{12}\) + \(\dfrac{1}{20}\) + \(\dfrac{1}{30}\) + \(\dfrac{1}{42}\) + \(\dfrac{1}{56}\) + \(\dfrac{1}{72}\)

D = \(\dfrac{1}{1.2}\) + \(\dfrac{1}{2.3}\) + \(\dfrac{1}{3.4}\) + \(\dfrac{1}{4.5}\) + \(\dfrac{1}{5.6}\) + \(\dfrac{1}{6.7}\)+\(\dfrac{1}{7.8}\)\(\dfrac{1}{8.9}\)

D = \(\dfrac{1}{1}\) - \(\dfrac{1}{2}\)+\(\dfrac{1}{2}\)-\(\dfrac{1}{3}\)+\(\dfrac{1}{3}\)-\(\dfrac{1}{4}\)+\(\dfrac{1}{4}\)-\(\dfrac{1}{5}\)+\(\dfrac{1}{5}\)-\(\dfrac{1}{6}\)+\(\dfrac{1}{6}\) - \(\dfrac{1}{7}\)+\(\dfrac{1}{7}\)-\(\dfrac{1}{8}\)+\(\dfrac{1}{8}\)-\(\dfrac{1}{9}\)

D = \(\dfrac{1}{1}\) - \(\dfrac{1}{9}\)

D = \(\dfrac{8}{9}\)

E = \(\dfrac{3}{2.4}\)+\(\dfrac{3}{4.6}\)+\(\dfrac{3}{6.8}\)+...+\(\dfrac{3}{98.100}\)

E = \(\dfrac{3}{2}\) \(\times\) ( \(\dfrac{2}{2.4}\) + \(\dfrac{2}{4.6}\)\(\dfrac{2}{6.8}\)+...+\(\dfrac{2}{98.100}\))

E = \(\dfrac{3}{2}\)\(\times\)\(\dfrac{1}{2}\) - \(\dfrac{1}{4}\)\(\dfrac{1}{4}\) - \(\dfrac{1}{6}\)+\(\dfrac{1}{6}\)-\(\dfrac{1}{8}\)+...+\(\dfrac{1}{98}\) - \(\dfrac{1}{100}\))

E = \(\dfrac{3}{2}\) \(\times\) ( \(\dfrac{1}{2}\) - \(\dfrac{1}{100}\))

E = \(\dfrac{3}{2}\) \(\times\) \(\dfrac{49}{100}\)

E = \(\dfrac{147}{200}\)

27x36+15x72-36x47

=27x36+15x2x36-36x47

=27x36+30x36-36x47

=36x(27+30-47)

=36x10

=360

26 tháng 11 2019

Cảm ơn

27 tháng 11 2019

*Lưu ý: "." là dấu nhân nha!

  27.36+15.72-36.47

=27.36+15.2.36-36.47

=27.36+30.36-36.47

=36.(27+30-47)

=36.10

=360

Chúc em học tốt!

#Dũng#

a, 27x 36 + 73 x 99 + 27 x 14 - 49 x 73    

= 27 ( 36 + 14 ) + 73 ( 99 - 49 )  = 27 x 50  +  73 x 50

= 50 ( 27 + 73)  = 50 x 100  = 5 000 

   b, 21 x (271 + 29 ) + 79 x ( 271 + 29)

=   (271 + 29 ) (  21 + 79)

=   300 x  100 =  30 000

18 tháng 3 2016

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18 tháng 3 2016

trả lời cẩn thận đi minato

14 tháng 10 2021

\(C=\dfrac{10}{7\cdot12}+\dfrac{10}{12\cdot17}+...+\dfrac{10}{502\cdot507}\)

\(=2\left(\dfrac{1}{7}-\dfrac{1}{12}+\dfrac{1}{12}-\dfrac{1}{17}+...+\dfrac{1}{502}-\dfrac{1}{507}\right)\)

\(=2\cdot\dfrac{500}{3549}=\dfrac{1000}{3549}\)