= -97/1176 ^{lớp 4 học số âm à???}

-97/1176 

-97/1176 

-6/35

1/5x (4/7- 3/7- 1)=1/5x -6/7= -6/35

\(-\dfrac{6}{35}\)

\(\dfrac{1}{5}\times\dfrac{4}{7}+\dfrac{3}{7}\times\dfrac{1}{5}-\dfrac{1}{5}\)

\(=\dfrac{4}{35}+\dfrac{3}{35}-\dfrac{1}{5}\)

\(=\dfrac{7}{35}-\dfrac{1}{5}\)

\(=\dfrac{1}{5}-\dfrac{1}{5}\)

\(=0\)

0

5/6 x 1/7 - 1/7 x 1/6

= 1/7 x (5/6 - 1/6)

= 1/7 x 2/3

= 2/21

 

8/15 : 4/5 x 3/2

= 2/3 x 3/2

= 1

a: =1/7(5/6-1/6)=1/7x2/3=2/21

b: =8/15x5/4x3/2=1

`5/6xx1/7-1/7xx1/6`

`= 1/7 xx (5/6-1/6)`

`= 1/7 xx 2/3`

`= 2/21`

`8/15: 4/5 xx3/2`

`= 2/3 xx 3/2`

`= 1`

 

2/7

11/21

2/7

11/21

2/7

11/21

\(=\dfrac{3}{7}\times\left(\dfrac{1}{5}+\dfrac{2}{3}-\dfrac{1}{8}\right)\\ =\dfrac{3}{7}\times\left(\dfrac{24}{5\times24}+\dfrac{2\times40}{3\times40}-\dfrac{15}{8\times15}\right)\\ =\dfrac{3}{7}\times\left(\dfrac{24+80-15}{120}\right)\\ =\dfrac{3}{7}\times\dfrac{89}{120}\\ =\dfrac{89}{280}\)

\(\dfrac{3}{7}\times\dfrac{1}{5}+\dfrac{2}{3}\times\dfrac{3}{7}-\dfrac{3}{7}\times\dfrac{1}{8}\)
\(=\dfrac{3}{7}\times\left(\dfrac{1}{5}+\dfrac{3}{7}-\dfrac{1}{8}\right)\)
\(=\dfrac{3}{7}\times\dfrac{56+120-35}{280}\)
\(=\dfrac{3}{7}\times\dfrac{141}{280}\)
\(=\dfrac{423}{1960}\)

suy ra A=1/23+1/7-1/1009.23.7.1009 phần 1/23+1/7-1/1009+1/7.1/3/1/1009 .23.7.1009+1/30.1009-160

suy ra A=7.1009+23.1009-23.7/7.1009+23.1009-23.7+1               +1/7.1009+23.1009-23.7+1=7/1009+23.1009- 23.7+1/7.1009+23.1009-23.7+1=1 

1009.23.717.231009.231009.71009.23.723.71009.71009.23+−+−+=A Xem nội dung đầy đủ tại: http://123doc.org/document/1622115-de-dap-an-hsg-toan-6-y6-1.htm+ Xem nội dung đầy đủ tại: http://123doc.org/document/1622115-de-dap-an-hsg-toan-6-y6-1.htm11611009).237(1 Xem nội dung đầy đủ tại: http://123doc.org/document/1622115-de-dap-an-hsg-toan-6-y6-1.htm

  1/2x1/3+1/3x1/4+1/4x1/5+1/5x1/6+1/6x1/7+1/7x1/8+1/8x1/9

=7/18