2424

cách làm = máy tính

\(6*8*5/9*24*10=1/9\) Tương tự vs các câu còn lại nhé =)

a: \(=\dfrac{6}{24}\cdot\dfrac{8}{9}\cdot\dfrac{5}{10}=\dfrac{1}{8}\cdot\dfrac{8}{9}=\dfrac{1}{9}\)

b: \(=\dfrac{12}{18}\cdot\dfrac{14}{21}\cdot13=\dfrac{2}{3}\cdot\dfrac{2}{3}\cdot13=\dfrac{52}{9}\)

c: \(=\dfrac{2323}{4646}\cdot\dfrac{123123}{234234}=\dfrac{1}{2}\cdot\dfrac{123}{234}=\dfrac{41}{156}\)

  35 x 12 - 15 x 28 + \(\frac{2323}{4949}-\frac{23}{49}\)+ 2010 

=  (420 - 420 )+ \(\left(\frac{23}{49}-\frac{23}{49}\right)\)+ 2010

= 0 + 0 + 2010 = 2010 .

35 x 12 -15 x28+2323/4949-23/49+2010

=35x12-15x28+23/49-23/49+2010

=420-420+0+2010

=0+0+2010

=2010

35.12-15.28+ 23.101/49.101-23/49+2010=

=7.5.4.3 - 3.4.4.7+23/49-23/49+2010=

=2010

2323/202+2323/606+2323/1212+2323/2020+2323/3030+2323/4242+2323/5656+2323/7272+2323/9090.=

\(\frac{23\times101}{2\times101}+\frac{23\times101}{6\times101}+\frac{23\times101}{12\times101}+....+\frac{23\times101}{72\times101}+\frac{23\times101}{90\times101} \)

=\(\frac{23}{2}+\frac{23}{6}+..........+\frac{23}{72}+\frac{23}{90}\)

=\(23\times\left(\frac{1}{1\times2}+\frac{1}{2\times3}+.....+\frac{1}{9\times10}\right)\)

=\(23\times\left(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+...+\frac{1}{9}-\frac{1}{10}_{ }\right)\)

=\(23\left(1-\frac{1}{10}\right)_{ }\)

=\(23\times\frac{9}{10}\)

==\(\frac{207}{10}\)           

chúc học giỏi nha bn

8.07605229591837

=15/23.(69/54./27/15)

=15/23.23/10

=3/2

\(=\dfrac{15}{23}\times\dfrac{69}{54}\times\dfrac{27}{15}\\ =\dfrac{3}{2}\)

=15/23 x (69/54 x /27/15)

=15/23 x 23/10

=3/2

A, chờ tí nha 

B, rút gọn phân số ta được

= 27 . \(\frac{17}{27}\)- \(\frac{37}{36}\)

= 17 - \(\frac{36}{37}\)= \(\frac{649}{36}\)

tu lam

A,  2005 x 2006 - 1 / 2006 x 2004 + 2005

= \(\frac{4022030}{1}\)- \(\frac{1}{4022029}\)

ta thấy 1 x1 = 1 4022030 - 1 = 4022029 

4022030 x 4022029 = .... : 4022029 = 4022030 

=> \(\frac{4022030-}{4022029\times1}1\)= 1 

a)\(\left(\dfrac{1}{9}:\dfrac{8}{27}\right):\left(\dfrac{16}{48}:\dfrac{8}{21}\right)\)

=\(\dfrac{3}{8}:\dfrac{7}{8}\)

=\(\dfrac{3}{7}\)

b)\(\dfrac{19}{23}+\dfrac{1}{9}\cdot\dfrac{36}{23}\)

=\(\dfrac{19}{23}+\left(\dfrac{1}{9}\cdot\dfrac{36}{23}\right)\)

=\(\dfrac{19}{23}+\left(\dfrac{1}{1}\cdot\dfrac{4}{23}\right)\)

=\(\dfrac{19}{23}+\dfrac{4}{23}\)

=\(\dfrac{23}{23}=1\)

c)\(\left(\dfrac{13}{23}+\dfrac{1313}{2323}-\dfrac{131313}{232323}\right)\cdot\left(\dfrac{1}{3}+\dfrac{1}{4}-\dfrac{7}{12}\right)\)

=\(\left(\dfrac{13}{23}+\dfrac{1313}{2323}-\dfrac{131313}{232323}\right)\cdot\left(\dfrac{4}{12}+\dfrac{3}{12}-\dfrac{7}{12}\right)\)

=\(\left(\dfrac{13}{23}+\dfrac{1313}{2323}-\dfrac{131313}{232323}\right)\cdot0\)

=0

chúc bn học tốt!