a) -1/24 - [ 1/4 - ( 1/2 - 7/8 )]

= -1/24 - [ 1/4 +3/8 ]

= -1/24 - 5/8

= -2/3.

a) -1/24 - [ 1/4 - ( 1/2 - 7/8 )]

= -1/24 - [ 1/4 +3/8 ]

= -1/24 - 5/8

= -2/3.

Xin lỗi nha chỉ có thời gian làm câu a) thôi

\(=\left(-2-\dfrac{7}{12}\right):\dfrac{15}{7}-\dfrac{1}{18}:\dfrac{15}{7}+\dfrac{20}{9}:\dfrac{15}{7}\)

\(=\dfrac{7}{15}\left(-2-\dfrac{7}{12}-\dfrac{1}{18}+\dfrac{20}{9}\right)\)

\(=\dfrac{7}{15}\cdot\dfrac{-72-21-2+80}{36}=\dfrac{7}{15}\cdot\dfrac{-15}{36}=\dfrac{-7}{36}\)

\(\left(-2\dfrac{7}{12}\right):2\dfrac{1}{7}-\dfrac{1}{18}:2\dfrac{1}{7}+2\dfrac{2}{9}:2\dfrac{1}{7}\)

\(=\left(-2\dfrac{7}{12}-\dfrac{1}{18}+2\dfrac{2}{9}\right):2\dfrac{1}{7}\)

\(=\left(\dfrac{-31}{12}-\dfrac{1}{18}+\dfrac{20}{9}\right):2\dfrac{1}{7}\)

\(=-\dfrac{5}{12}:\dfrac{15}{7}\)

\(=-\dfrac{5}{12}\cdot\dfrac{7}{15}\)

\(=-\dfrac{7}{36}\)

\(\dfrac{2}{7}:\dfrac{1}{4}-\dfrac{1}{7}=\dfrac{2}{7}x\dfrac{4}{1}-\dfrac{1}{7}=\dfrac{8}{7}-\dfrac{1}{7}=\dfrac{7}{7}=1\)

\(\dfrac{7}{11}x0+\dfrac{5}{9}:\dfrac{1}{2}=0+\dfrac{5}{9}x\dfrac{2}{1}=\dfrac{10}{9}\)

\(\left(\dfrac{3}{7}+\dfrac{1}{4}\right):\dfrac{3}{4}=\left(\dfrac{12}{28}+\dfrac{7}{28}\right)x\dfrac{4}{3}=\dfrac{19}{28}x\dfrac{4}{3}=\dfrac{19}{21}\)

\(\dfrac{4}{3}x\dfrac{1}{2}+\dfrac{7}{2}:\dfrac{1}{4}=\dfrac{4}{6}+\dfrac{7}{2}x\dfrac{4}{1}=\dfrac{2}{3}+\dfrac{14}{1}=\dfrac{2}{3}+14=14\dfrac{2}{3}=\dfrac{44}{3}\)

cảm ơn nhé

2 + 5 = 7     1 + 4 = 5     7 - 6 = 1

7 - 3 = 4     6 + 1 = 7     7 - 4 = 3

4 + 3 = 7     5 + 2 = 7     7 - 0 = 7

\(\left(\dfrac{5}{7}-\dfrac{7}{7}\right)-\left[0,2-\left(-\dfrac{2}{7}-\dfrac{1}{10}\right)\right]\)

=\(-\dfrac{2}{7}-\left[\dfrac{1}{5}+\dfrac{2}{7}+\dfrac{1}{10}\right]\)  

=\(-\dfrac{2}{7}-\dfrac{1}{5}-\dfrac{2}{7}-\dfrac{1}{10}\) 

=\(\left(-\dfrac{2}{7}-\dfrac{2}{7}\right)-\left(\dfrac{1}{5}+\dfrac{1}{10}\right)\) 

=\(-\dfrac{4}{7}-\left(\dfrac{2}{10}+\dfrac{1}{10}\right)\) 

=\(-\dfrac{4}{7}-\dfrac{3}{10}\) 

=\(-\dfrac{40}{70}-\dfrac{21}{70}\)

=\(-\dfrac{61}{70}\)

   (3 - \(\dfrac{1}{4}\) + \(\dfrac{2}{3}\)) - (5 - \(\dfrac{1}{3}\) - \(\dfrac{5}{6}\)) - (6 - \(\dfrac{7}{4}\) - \(\dfrac{3}{2}\))

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

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

= - 8  + \(\dfrac{3}{2}\) + 1 + \(\dfrac{3}{2}\) + \(\dfrac{5}{6}\)

= (- 8 + 1) + (\(\dfrac{3}{2}\) + \(\dfrac{3}{2}\)) + \(\dfrac{5}{6}\)

= -7 + 3 + \(\dfrac{5}{6}\)

= - 4 + \(\dfrac{5}{6}\)

= \(\dfrac{-19}{6}\)

Lời giải chi tiết:

bang gi ong cung chiu vi ong hoc lop 5

D= (1-1/7).(1-2/7).(1-3/7)...(1-10/7)

 = 6/7 . 5/7 . 4/7 ..... ( -3/7)

 = 6.5.4.3.2.1.0.(−1).(−2).(−3)7 

Vì só nào nhân với 0 cũng bằng 0 

=> 6.5.4.3.2.1.0.(−1).(−2).(−3)7 

= 07 =0

Lời giải chi tiết:

7 > 6                                                      7 > 4

2 < 5                                                       5 < 7

7 > 3                                                      3 > 1

6 = 6                                                        6 < 7