a) (-18)+(-31)+98+|-18|+(-69)

((-18)+98)+((-31)+18+(-69))

80+ (-82)

-2

b)15×(-176)+15×76+100×15

=15×((-176)+76+10)

=15×0

=0

c)79×89-79×(-11)-100×79

=79×(89-(-11)-100)

=79×0

=0

Chúc bạn học tốt

a) (-18)+(-31)+98+|-18|+(-69)

=(-18)+(-31)+98+18+(-69)

=[(-18)+18]+[(-31)+(-69)]+98

=0+(-100)+98

=-2

b) 15.(-176)+15.76+100.15

=15[(-176)+76+100]

=15.0=0

c) 79.89-79.(-11)-100.79

=19.[89-(-11)-100]

=19.0=0

tính nhanh

a, 53 . 84 + 212 . 29

=  4452 + 6148

= 10600

b, 79 . 17 + 21 . 18 

= 1343 + 378

= 1721 

c, 16 + 21 + 26  + 31 + ... + 96 + 101

= ( 101 + 16 ) x 18  2 

= 1053 

2 . 17 . 12 + 4. 6 . 21 + 8 . 3 . 62

= ( 2. 12 ) . 17 + ( 4 . 6 ) . 21 + ( 8 . 3 ) . 62

= 24 . 17 + 24 . 21 + 24 .62

=  24. ( 17 + 21 + 62 )

= 24 . 100

= 2400

37 . 24 + 37 . 76 + 63 . 79 + 63 . 21

= 37 . ( 24 + 76 ) + 63 . ( 79 + 21 ) 

= 37 . 100 + 36 . 100

= ( 37 + 63 ) . 100

= 100 . 100

= 10000

   2 . 17 . 12 + 4. 6 . 21 + 8 . 3 . 62

= ( 2. 12 ) . 17 + ( 4 . 6 ) . 21 + ( 8 . 3 ) . 62

= 24 . 17 + 24 . 21 + 24 .62

=  24. ( 17 + 21 + 62 )

= 24 . 100 = 2400

   37 . 24 + 37 . 76 + 63 . 79 + 63 . 21

= 37 . ( 24 + 76 ) + 63 . ( 79 + 21 ) 

= 37 . 100 + 36 . 100

= ( 37 + 63 ) . 100

= 100 . 100 = 10000

      ~ Chúc bn học tốt!! ^^ ~

A, (-25). 21. (-2)2. (-|-3|). (-1)2015

B, (-5)3. 67. (-|-2|). (-1)2014

C, 35.18 – 5.7.28 + 35. (-90)

D, 24. (16 – 5) – 16. (24 – 5)

E, - 79. (73 – 27) – 73. (-79 + 27) 

G, 31. (-18) + 31. (-8)-31

M, -48 + 48. (-78) + 48. (-21)

N, -|-17| + 2. [ 24: (-8) + (-5)2]

I, -|-7|. [(-2)4 + (-36): (-32)] – (-5)3

21.300+79.300

300(21+79)

300.100

30000

t nha 

21.(271+29)+79.(271+29)

=(271+29).(21+79)

=300.100

=30000

a) -48 + (-35 + 19) - (32 + 45 + 21)

= -48 - 35 + 19 - 32 - 45 - 21

= (-48 - 32) - (35 + 45) + (19 - 21)

= -80 - 80 - 2

= -162

b) -47 + (38 - 13) - (-52 + 31 - 91)

= -47 + 38 - 13 + 52 - 31 + 91

= (-47 - 13) + (38 + 52) - 31

= -60 + 90 - 31

= 30 - 31 = -1

c) 54 + (-37) - (+70) + (-163) - (-246) + (-230

= 54 - 37 - 70 - 163 + 246 - 230

= (54 + 246) - (37 + 163) - (70 + 230)

= 300 - 200 - 300

= -200

còn lại tự lm

Tính hợp lý :

A, (-48)+(-35+19)-(32+45+21)

B, (-47)+(38-13)-(-52+31-91)

C, 54+(-37)-(+70)+(-163)-(-246)+(-230

1.

a)=315-315-200-(21+79)=-200-100=-300

b)=413-413-210+70+30=-210+100=-110

2.

a)x=-9+7=-2

b)x=21+5=26

  \(29.\left(79-34\right)-79.\left(29+34\right)\)

\(=29.79-29.34-79.29-79.34\)

\(=0-34.\left(29+79\right)\)

\(=0-34.108\)

\(=0-3672\)

\(=-3672\)

\(29.\left(79-34\right)-79.\left(29+34\right)\)

\(=29.79-29.34-79.29-79.34\)

\(=\left(29.79-79.29\right)-34.\left(29+79\right)\)

\(=0-34.108\)

\(=0-3672\)

\(=-3672\)