Đố các con có thể giải bài này
C1: thực hiện phép tính
a. 29.87 + 29 . ( - 17 )
b. 31. ( - 16 ) + 31 . ( - 83 ) - 31
c. 123. ( - 29 ) - 23 . ( - 29 )
d. ( - 12 ( . 47 + ( - 12 ). 52 + ( - 12 )
e ( - 105 ) . 19 + ( - 76 ) . 105 - 5 . 105
f. ( - 27 ) . 72 + 27 . ( - 19 )- 279
C2 : thực hiện phép tính
c. 2002 - { 474 - 40 . [ 3^4 - ( 8^2 + 7 ) ] + 14^2 : 7 }
d. 307 - [ ( 180.4^0 - 160 ) : 2^2 + 9 ] : 2
Câu 1
a) \(29.87+29.\left(-17\right)\)
\(=29.\left(87-17\right)\)
\(=29.70\)
\(=2030\)
b) \(31.\left(-16\right)+31.\left(-83\right)-31\)
\(=31.\left(-16-83-1\right)\)
\(=31.\left(-100\right)\)
\(=-3100\)
c) \(123.\left(-29\right)-23.\left(-29\right)\)
\(=-29.\left(123-23\right)\)
\(=-29.100\)
\(=-2900\)
d) \(-12.47+\left(-12\right).52+\left(-12\right)\)
\(=-12.\left(47+52+1\right)\)
\(=-12.100\)
\(=-1200\)
e) \(\left(-105\right).19+\left(-76\right).105-5.105\)
\(=-105.\left(19+76+5\right)\)
\(=-105.100\)
\(=-10500\)
f) Sửa đề:
\(-27.72+27.\left(-19\right)-27.9\)
\(=-27.\left(72+19+9\right)\)
\(=-27.100\)
\(=-2700\)
Câu 2
c) \(2002-\left\{474-40.\left[3^4-\left(8^2+7\right)\right]+14^2:7\right\}\)
\(=2002-\left\{474-40.\left[81-\left(64+7\right)\right]+196:7\right\}\)
\(=2002-\left[474-40.\left(81-71\right)+28\right]\)
\(=2002-\left(474-40.10+28\right)\)
\(=2002-\left(474-400+28\right)\)
\(=2002-102\)
\(=1900\)
d) \(307-\left[\left(180.4^0-160\right):2^2+9\right]:2\)
\(=307-\left[\left(180.1-160\right):4+9\right]:2\)
\(=307-\left[\left(180-160\right):4+9\right]:2\)
\(=307-\left(20:4+9\right):2\)
\(=307-\left(5+9\right):2\)
\(=307-14:2\)
\(=307-7\)
\(=300\)
