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26 tháng 4 2016

5 / 14 + 18 / 35 + ( 5 / 4 - 5 / 4 ) : ( 5/12)^2

= 61 / 70 + 0 : ( 5 / 12)^2

= 61 / 70 + 0

= 61 / 70

c) Ta có: \(\dfrac{3}{5}+\dfrac{-5}{20}+\dfrac{30}{75}+\dfrac{-7}{4}\)

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

\(=1-2=-1\)

Giải:

a)-1/12+4/3=-1/12+16/12=15/12=5/4

b)(-4/14-3/15)-(1/5-20/35-(-1)).7

=-17/35-22/35.7

=-17/35-22/5

=-171/35

c)3/5+-5/20+30/75+-7/4

=3/5+-1/4+2/5+-7/4

=(3/5+2/5)+(-1/4+-7/4)

=1+-2

=-1

d)5/6.-12/14+7/13

=-5/7+7/13

=-16/91

e)2/-9-5/-36-1/4

=-1/12-1/4

=-1/3

f)2/23+-5/12+7/18+21/23+-7/12

=(2/23+21/23)+(-5/12+-7/12)+7/18

=1+-1+7/18

=7/18

20 tháng 7 2023

1)1/6 - - 5/6 = 1/6 + 5/6 = 1

2)6/13 - -14/39 = 6/13 + 14/39= 32/39

3)4/5 - 4/-18 = 4/5 + 4/18= 46/45

4)7/21 - 9/-36 = 7/21 + 9/36 = 7/12

5)-12/18 - -21/35  = -12/18 + 21/35 = -1/15

6)-3/21 - 6/42 = -2/7

7)-18/24 - 15/21 = -41/28

8)1/6 - 2/5 =-7/30

27 tháng 3

a; \(\dfrac{9}{4}\) - \(\dfrac{-11}{4}\)

\(\dfrac{9}{4}\) + \(\dfrac{11}{4}\)

\(\dfrac{20}{4}\)

= 5 

b; \(\dfrac{7}{8}\) - \(\dfrac{3}{-8}\) - \(\dfrac{1}{8}\)

=  \(\dfrac{7}{8}\) + \(\dfrac{3}{8}\) - \(\dfrac{1}{8}\)

\(\dfrac{7+3-1}{8}\)

\(\dfrac{9}{8}\) 

27 tháng 3

c; \(\dfrac{-5}{21}\) - \(\dfrac{25}{21}\) - \(\dfrac{-1}{21}\)

  = \(\dfrac{-5}{21}\) - \(\dfrac{25}{21}\) + \(\dfrac{1}{21}\)

 =  \(\dfrac{-5-25+1}{21}\)

\(\dfrac{-29}{21}\)

26 tháng 12 2018

a) 47 - [ (45.24 - 52.12) : 14 ]

= 47 - ( 420 : 14 )

= 47 - 30

= 17

26 tháng 12 2018

b) |-18| + (-12)

= 18 - 12

= 6

HQ
Hà Quang Minh
Giáo viên
7 tháng 10 2023

a) \(\frac{{ - 3}}{7}.\frac{2}{5} + \frac{2}{5}.\left( { - \frac{5}{{14}}} \right) - \frac{{18}}{{35}}\)

\(\begin{array}{l} = \frac{2}{5}.\left( {\frac{{ - 3}}{7} + \frac{{ - 5}}{{14}}} \right) - \frac{{18}}{{35}}\\ = \frac{2}{5}.\left( {\frac{{ - 6}}{{14}} + \frac{{ - 5}}{{14}}} \right) - \frac{{18}}{{35}}\\ = \frac{2}{5}.\frac{{ - 11}}{{14}} - \frac{{18}}{{35}} = \frac{{ - 11}}{{35}} - \frac{{18}}{{35}} =  \frac{{ -29}}{{35}}\end{array}\)

b) \(\left( {\frac{2}{3} - \frac{5}{{11}} + \frac{1}{4}} \right):\left( {1 + \frac{5}{{12}} - \frac{7}{{11}}} \right)\)

\(\begin{array}{l} = \left( {\frac{{2.11.4}}{{3.11.4}} - \frac{{5.3.4}}{{11.3.4}} + \frac{{1.3.11}}{{4.3.11}}} \right):\left( {\frac{11.12}{11.12} + \frac{{5.11}}{{12.11}} - \frac{{7.12}}{{11.12}}} \right)\\ = \left( {\frac{{88 - 60 + 33}}{{121}}} \right):\left( { \frac{{121+55 - 84}}{{121}}} \right)\\ = \frac{{61}}{{121}}:\frac{{92}}{{121}} = \frac{{61}}{{121}}.\frac{{121}}{{92}}= \frac{{61}}{{92}}\end{array}\)

c) \(\left( {13,6 - 37,8} \right).\left( { - 3,2} \right)\)

\( = \left( { - 24,2} \right).\left( { - 3,2} \right) = 77,44\)

d) \(\left( { - 25,4} \right).\left( {18,5 + 43,6 - 16,8} \right):12,7\)

\(\begin{array}{l} = \left( { - 25,4} \right).\left( {62,1 - 16,8} \right):12,7\\ = \left( { - 25,4} \right).45,3:12,7\\ = \left( { - 25,4} \right):12,7.45,3\\ =  (- 2).45,3 =  - 90,6\end{array}\)

a: \(=\dfrac{2}{5}\cdot\left(-\dfrac{3}{7}-\dfrac{5}{14}\right)-\dfrac{18}{35}\)

\(=\dfrac{2}{5}\cdot\dfrac{-6-5}{14}-\dfrac{18}{35}\)

\(=\dfrac{2}{5}\cdot\dfrac{-11}{14}-\dfrac{18}{35}=-\dfrac{22}{70}-\dfrac{18}{35}=\dfrac{-58}{70}=-\dfrac{29}{35}\)

b: \(=\dfrac{88-60+33}{132}:\dfrac{132+55-84}{132}\)

\(=\dfrac{61}{132}\cdot\dfrac{132}{103}=\dfrac{61}{103}\)

c: \(=-24.2\cdot\left(-3.2\right)=24.2\cdot3.2=77.44\)

d: \(=\dfrac{-25.4}{12.7}\cdot45.3=-2\cdot45.3=-90.6\)

29 tháng 11 2017

1) \(-452-\left(-67+75-452\right)\)

\(=-452+67-75+452\)

\(=-\left(452-67\right)-75+452\)

\(=-385-75+452\)

\(=-\left(385+75\right)+452\)

\(=-460+452\)

\(=-\left(460-452\right)\)

\(=-8\)

b) \(35-\left\{12-\left[-14+\left(-2\right)\right]\right\}\)

\(=35-\left[12-\left(-14-2\right)\right]\)

\(=35-\left\{12-\left[-\left(14+2\right)\right]\right\}\)

\(=35-\left[12-\left(-16\right)\right]\)

\(=35-\left(12+16\right)\)

\(=35-28\)

\(=7\)

c) \(-\left|-5\right|+\left(-19\right)+18+\left|11-4\right|-57\)

\(=-5-19+18+\left|7\right|-57\)

\(=-5-19+18+7-57\)

\(=-\left(5+19\right)+18+7-57\)

\(=-24+18+7-57\)

\(=-\left(24-18\right)+7-57\)

\(=-6+7-57\)

\(=-\left(6-7\right)-57\)

\(=-\left(-1\right)-57\)

\(=1-57\)

\(=-57+1\)

\(=-\left(57-1\right)\)

\(=-56\)

29 tháng 11 2017

Mình đặt tên a,b,c cho 3 ý cho dễ gọi nha.

a,\(-452-\left(-67+75-452\right)\)

\(=-452+67-75+452\)

\(=-8\)

b,\(35-\left\{12-\left[-14+\left(-2\right)\right]\right\}\)

\(=35-\left(12+14-2\right)\)

\(=35-24\)

\(=11\)

c,\(-\left|-5\right|+\left(-19\right)+18+\left|11-4\right|-57\)

\(=-5-19+18+7-57\)

\(=-56\)

31 tháng 10 2019

Học sinh nhẩm và ghi:

16 : 4 =4

18 : 2 =9

24 : 6 =4

16 : 2 =8

18 : 6 =3

24 : 4 =6

12 : 6 =2

15 : 5 =3

35 : 5 = 7