tính:
a) 1990.1990 - 1992 .1988
b) (124 .237 +152):(870 + 235 .122)
1990x1990 - 1992 x 1998
(124 x 237 + 152 ) : (870 + 235 x 122)
1990 x 1990 - 1992 x 1998
= 1990 x 1990 - ( 1992 - 2 ) x ( 1998 + 2 )
= 1990 x 1990 - 1990 x 2000
= 1990 x ( 2000 - 1990 )
= 1990 x 10
= 1900
( 124 x 237 + 152 ) : ( 870 + 235 x 122 )
= ( 124 x 235 + 248 + 152 ) : ( 235 x 124 + 400)
= ( 124 x 235 + 400 ) : ( 235 x 124 + 400)
= 1
a. ( a + 1 ) + ( a + 2 ) + ( a + 3 ) + ... ( a + 100 ) = 5750
b. 1990.1990 - 1992 . 1988
c. ( 124 . 237 + 152 ) : ( 870 + 235 . 122 )
d. 75. ( x + 157 ) = 24450
e. 14700 : ( x + 47 ) = 84
f. 35320 - x . 72 = 13072
- xin lỗi nhé, giúp tớ.
a. (a+1)+(a+2)+..+(a+100)=5750
(a+a+a+a+..+a)+(1+2+3+..+100)=5750
a.100+5050=5750
a.100=5750-5050
a.100=700
a=700/100
a=7
(124*237+152)/(870+235*122)
(124*237+152)/(870+235*122)
=(29388+152)/(870+28670)
=29540/29540
=1
Tính nhanh:
a)1990*1990+1992*1998
b) (1374*57+687*86):(26*13+74*14)
c) (124*237+152):(870+235*122)
(124 x 237 + 152 ) : ( 870 + 235 x 122 )
(124 x 237 + 152 ) : (870 = 235 x 122
= (29388 + 152) : ( 870 + 28670 )
= 29540 : 29540
= 1
Tính nhanh: (124 x 237 + 152) : (870 + 235 x 122)
= 29540 : 29540
= 1
nhớ k cho mik vs nha Hải Yến
( 124 x 237 + 152 ) : ( 870 + 235 x 122)
=[124 x (235+2) + 152 ] : [870 + 235 x (124-2)]
=[124 x 235+124x2 + 152 ] : [870 + 235 x124 - 235x2]
=[124 x 235+248 + 152 ] : [870 + 235 x 124 - 470]
=[124 x 235+ 400 ] : [870 - 470 + 235 x 124 ]
=[124 x 235+ 400 ] : [400 + 235 x 124 ]
=1
( 124 x 237 + 152 ) : ( 870 + 235 x 122 )
= ( 29388 + 152 ) : ( 870 + 28670 )
= 29540 : 29540
= 1
Tính bằng cách hợp lí ( 124 x 237 + 152 ) : ( 870 + 235 x 122 )
(124 x 237 + 152) : (870 + 235 x 122) =
(124 x 235 + 248 + 152) : (235 x 124 + 400) =
(124 x 235 + 400) : (235 x 124 + 400) = 1
tic mk nhé
( 124 x 237 + 152 ) : ( 870 + 235 x 122 )
= (29388 + 152 ) : ( 870 + 28670)
= 29540 : 29540
= 1
Tick cho tớ nha
﴾ 124 x 237 + 152 ﴿ : ﴾ 870 + 235 x 122 ﴿
= ﴾29388 + 152 ﴿ : ﴾ 870 + 28670﴿
= 29540 : 29540
= 1
Tính nhanh:
Câu a: 1990 x 1990 - 1992 x 1988
Câu b: ( 1374 x 57 + 687 x 86 ) : ( 26 x 13 + 74 x 14 )
Câu c: ( 124 x 237 + 152 ) : ( 870 + 235 : 122 )
Tính nhanh ( 124 . 237 + 152 ) : ( 870 + 235 . 122 )
= (31.4.237 + 4.38) : (435.2 + 2.235.61)
= [4.(31.237 + 38)] : [2.(435 + 61.235)]
= (4.7385) : (2.14770)
= 29540 : 29540
= 1