b, -418 - {- 418 - [ -418 - (-418) + 2021]}

= -481 - { -418  - [ 0 + 2021]}

= -481 + 418 + 2021

= 2021 

d, 23 - 501 - 343 + 61 - 257 + 16 - 499

=  (23 + 61 + 16) - (501 + 499) - (343 + 257)

= 100 - 1000 - 600

= 100 - 1600

= -1500 

e, 743 - 231 + (-495) - (-69) - 38 + (-117)

= 512 - 426 - 155

= 86 - 155

= - 69 

b: 200:[117-(23-6)]

=200:[117-17]

=200:100

=2

c: \(2020-\left\lbrack45-\left(6-1\right)^2\right\rbrack+2019^0\)

\(=2020-\left\lbrack45-5^2\right\rbrack+1\)

=2021-(45-25)

=2021-20

=2001

d: \(476-\left\lbrace5\cdot\left\lbrack409-\left(8\cdot3-21\right)^2\right\rbrack-1724\right\rbrace\)

=476-{5*[409-(24-21)^2]-1724}

=\(476-\left\lbrace5\cdot\left\lbrack409-9\right\rbrack-1724\right\rbrace\)

\(=476-\left(5\cdot400-1724\right)=476-\left(2000-1724\right)\)

=476-276

=200

200 +23 * 6 : 65 = 20,5846 ............tic nhe 

= 205846 nha

TÍCH NHA!

117 +68 + 23 = (117 +23) + 68 = 140 + 68 = 208.

117 + 68 + 23.

=(117+23)+68

=140+68

=208

a) 5 x 4 + 117 = 20 + 117

                   = 137

b) 200 : 2 – 75 = 100 – 75

                   = 25

\(\left(\frac{12}{199}+\frac{23}{200}-\frac{34}{201}\right)\left(\frac{1}{2}-\frac{1}{3}-\frac{1}{6}\right)\)

\(=\left(\frac{12}{199}+\frac{23}{200}-\frac{34}{201}\right)\left(\frac{6}{12}-\frac{4}{12}-\frac{2}{12}\right)\)

\(=\left(\frac{12}{199}+\frac{23}{200}-\frac{34}{201}\right).0\)

\(=0\)

khó hiểu thật đó nha

a) -12 . x = 36

x = 36 : (-12)

x = -3

b) 3 . x - ( - 117 - 23 ) = 23

3 . x - (-140) = 23

3 . x + 140 = 23

3 . x = 23 - 140

3 . x = -117

x = -117 : 3

x = -39

Học Tốt !

a) -12 . x = 36

            x = - 12 - 36

            x = (- 12) + (- 36) = - 48

b) 3 . x - ( - 117 - 23 ) = 23

    3 . x - [ (- 117) + (- 23) ] = 23

    3 . x - (- 140) = 23

    3 . x               = 23 + (- 140) = (- 117)

         x               = (- 117) : 3

         x               = - 39

a) 16.4 = 64

b) (-125).(-6) = 750

c) (-23).(-11) = 253

d) (-200).(-5) = 1000