BÀi 1:

a: (-243+345)-(257+(-55)-129)

=-243+345-257+55+129

=(-243-257)+(345+55)+129

=-500+400+129

=-100+129

=29

b: \(\left(-2\right)^3-45:\left(-3\right)^2-\left(-2019\right)^0\cdot\left(-1\right)^{2019}\)

\(=-8-\frac{45}{9}-1\cdot\left(-1\right)\)

=-8-5+1

=-13+1

=-12

c: \(\left\lbrack27\cdot\left(-67\right)+33\cdot\left(-27\right)\right\rbrack:\left(-30\right)\)

\(=\frac{-27\left(67+33\right)}{-30}\)

\(=\frac{9}{10}\cdot100=90\)

d: \(\left(1^2+2^2+\cdots+100^2\right)\left(3^4-9^2\right)\)

\(=\left(1^2+2^2+\cdots+100^2\right)\left(81-81\right)\)

=0

e: \(53\cdot47+53^2-2021^0\)

\(=53\left(53+47\right)-1\)

=5300-1

=5299

i: 38+(-21)+(-58)+(-6)

=(38-58)+(-21-6)

=-20-27

=-47

h: (2020+27)-[2020+(-73)]-129

=2020+27-2020+73-129

=100-129

=-29

Bài 2: Tính nhanh

a) 29 + 132 + 237 + 868 + 3

 = 29+(132+858)+(237+3)

=29+990+240

=1259

hình như bạn làm sai á

8 − 9 4 + 2 7 − − 6 − 3 7 + 5 4 − 3 + 2 4 − 9 7 = 8 − 9 4 + 2 7 + 6 + 3 7 − 5 4 − 3 − 2 4 + 9 7 = 8 + 6 − 3 − 9 4 − 5 4 − 2 4 + 2 7 + 3 7 + 9 7 = 11 − 4 + 2 = 9

c ) 86 . 47 - 86 . 17 + 30 . 14

= 86 . ( 47 - 17 ) + 30 . 14

= 86 . 30 + 30 . 14

= 30 . ( 86 + 14 ) 

= 30 . 100

= 3000

a/ \(\left(-27\right)+|-227|+\left(-84\right).\)

\(=\left(-27\right)+227+\left(-84\right)\)

\(=200+\left(-84\right)=116\)

b/ \(=2017+\left(729+\left(-1008\right)\right)\)

\(=2017+\left(-279\right)=1738\)

c/ \(=86.\left(47-17\right)+30.14\)

\(=80.30+30.14\)

\(=30.\left(80+14\right)\)

\(=30.94=2820\)

Nhớ k cho mình nhé! Thank you!!!