1) 5 + (-4) = 1

2) (-8) + 2 = -6

3) 8 + (-2) = 6

4) 11 + (-3) = 8

5) (-11) + 2 = -9

6) (-7) + 3 = -4

7) (-5) + 5 = 0

8) 11 + (-12) = -1

9) (-18) + 20 = 2

10) (15) + (-12) = 3

11) (-17) + 17 = 0

12) 16 + (-2) = 14

13) (30) + (-14) = 16

14) (-19) + 20 = 1

15) (-18) + 15 = -3

16) (10) + (-6) = 4

17) (-28) + 14 = -14

18) 15 + (-30) = -15

19) (15) + (-4) = 11

20) (-21) + 11 = -10

21) 8 + (-22) = -14

22) (-15) + 4 = -11

23) (-3) + 2 = -1

24) 17 + (-14) = 3

25) 17 + (-14) = 3

thế này đọc đc mới đỉnh

bai EZ​ qua

mà bài dài quá sao làm hết dc

[1-(3/4-2/3)] - [1-(5/3-1/4)] - [1-(4/3+3/4)]

\(=\left[1-\left(\frac{3}{4}-\frac{2}{3}\right)\right]-\left[1-\left(\frac{5}{3}-\frac{1}{4}\right)\right]-\left[1-\left(\frac{4}{3}+\frac{3}{4}\right)\right]\)

\(=\left[1-\frac{1}{12}\right]-\left[1-\frac{17}{12}\right]-\left[1-\frac{25}{12}\right]\)

\(=\frac{11}{12}-\left(-\frac{5}{12}\right)-\left(-\frac{13}{12}\right)\)

\(=\frac{11}{12}+\frac{5}{12}+\frac{13}{12}\)

\(=\frac{29}{12}\)

\(\dfrac{2}{3}-4\left(\dfrac{1}{2}+\dfrac{3}{4}\right)\\ =\dfrac{2}{3}-4.\dfrac{2+3}{4}\\ =\dfrac{2}{3}-4.\dfrac{5}{4}\\ =\dfrac{2}{3}-5\\ =\dfrac{2-15}{3}\\ =\dfrac{-13}{3}\)

`a)2/3-4(1/2+3/4)`

`=2/3-4*1/2-4*3/4`

`=2/3-2-3`

`=2/3-5`

`=2/3-15/3`

`=-13/3`

\(a,2010:\left(-5\right)+400-1\\ =-402+400-1\\ =-3\\ b,\dfrac{2}{3}+\dfrac{3}{4}.\left(-\dfrac{4}{9}\right)\\ =\dfrac{2}{3}-\dfrac{1}{3}\\ =\dfrac{1}{3}\\ c,\left(1-\dfrac{2}{3}-\dfrac{1}{4}\right)\left(\dfrac{4}{5}-\dfrac{3}{4}\right)^2\\ =\dfrac{1}{12}.\left(\dfrac{1}{20}\right)^2\\ =\dfrac{1}{12}.\dfrac{1}{400}\\ =\dfrac{1}{4800}\)

a) \(2010:\left(-5\right)+400-1=-400+400-1=-1\)

b) \(\dfrac{2}{3}+\dfrac{3}{4}\cdot\dfrac{-4}{9}=\dfrac{2}{3}+\dfrac{-1}{3}=\dfrac{1}{3}\)

c) \(\left(1-\dfrac{2}{3}-\dfrac{1}{4}\right)\cdot\left(\dfrac{4}{5}-\dfrac{3}{4}\right)^2=\dfrac{1}{12}\cdot\dfrac{1}{400}=\dfrac{1}{4800}\)

các bn giúp mk vs 

\(D=1-4+4^2-4^3+4^4-...+4^{2016}-4^{2017}\) (sửa \(2^{2017}\) thành \(4^{2017}\))

\(\Rightarrow D=\left(1-4\right)+4^2\left(1-4\right)+4^4\left(1-4\right)-...+4^{2016}\left(1-4\right)\)

\(\Rightarrow D=\left(-3\right)+4^2.\left(-3\right)+4^4.\left(-3\right)-...+4^{2016}.\left(-3\right)\)

\(\Rightarrow D=\left(-3\right)\left(1+4^2+4^4+...+4^{2016}\right)\)

\(\Rightarrow4D=\left(-3\right)\left(4+4^3+4^5+...+4^{2017}\right)\)

\(\Rightarrow4D+D=\left(-3\right)\left(1+4+4^2+4^3+4^4+...+4^{2016}+4^{2017}\right)\)

\(\Rightarrow5D=\left(-3\right)\dfrac{4^{2017+1}-1}{4-1}\)

\(\Rightarrow D=\left(-3\right)\dfrac{4^{2018}-1}{3.5}\)

\(\Rightarrow D=\left(-1\right)\dfrac{4^{2018}-1}{5}=\dfrac{1-4^{2018}}{5}\)

\(=2:\dfrac{3}{3}-\dfrac{1}{3}\)

\(=2\cdot\dfrac{2}{3}-\dfrac{1}{3}=1\)

\(=2\cdot\dfrac{3}{2}-\dfrac{1}{3}=3-\dfrac{1}{3}=\dfrac{8}{3}\)

\(\sqrt{4}:\dfrac{2}{3}-\dfrac{1}{3}\\ =2:\dfrac{2}{3}-\dfrac{1}{3}\\ =3-\dfrac{1}{3}\\ =\dfrac{8}{3}\)

1, 3/5 + -4/15 = \(\dfrac{9}{15}\)+ \(\dfrac{-4}{15}\)= \(\dfrac{5}{15}\)= \(\dfrac{1}{3}\)

2, -1/3 + 2/5 + 2/15= \(\dfrac{-5}{15}+\dfrac{6}{15}+\dfrac{2}{15}\)=\(\dfrac{3}{15}=\dfrac{1}{5}\)

3, -3/5 + 7/21 + -4/5 + 7/5= \(\dfrac{1}{3}\)

\(1.\dfrac{3}{5}+\dfrac{-4}{15}=\dfrac{9}{15}+\dfrac{-4}{15}=\dfrac{5}{15}=\dfrac{1}{3}\)

\(2.\dfrac{-1}{3}+\dfrac{2}{5}+\dfrac{2}{15}=\dfrac{-5}{15}+\dfrac{6}{15}+\dfrac{2}{15}=\dfrac{3}{15}=\dfrac{1}{5}\)

\(3.\dfrac{-3}{5}+\dfrac{7}{21}+\dfrac{-4}{5}+\dfrac{7}{5}=\left(\dfrac{-3}{5}+\dfrac{-4}{5}+\dfrac{7}{5}\right)+\dfrac{7}{21}=0+\dfrac{7}{21}=\dfrac{1}{3}\)

\(1,\dfrac{3}{5}+\dfrac{-4}{15}=\dfrac{9}{15}+\dfrac{-4}{15}\\ =\dfrac{9-4}{15}=\dfrac{1}{3}\\ 2,\dfrac{-1}{3}+\dfrac{2}{5}+\dfrac{2}{15}=\dfrac{-5}{15}+\dfrac{6}{15}+\dfrac{2}{15}\\ =\dfrac{3}{15}=\dfrac{1}{5}\)