Tính hợp lý:
15 x (4-7) -15 x (5-3)
73 x (8-59)-59 x(8-73)
24) 15 (4-7)- 15 (5-3)
25) 73(8-59) -59(8-73)
\(\text{24) 15 (4-7)- 15 (5-3)}\)
\(=15.\left[\left(4-7\right)-\left(5-3\right)\right]\)
\(=15.\left[4-7-5+3\right]\)
\(=15.\left(-5\right)\)
\(=-75\)
\(\text{25) 73(8-59) -59(8-73)}\)
\(=73.8-73.59-59.8+59.73\)
\(=8\left(73-59\right)+59\left(-73+73\right)\)
\(=8.14+59.0\)
\(=112\)
24) 15 (4-7)- 15 (5-3)
=15. 4 − 7 − 5 − 3
= 15. 4 − 7 − 5 + 3
= 15. −5
= −75
25) 73(8-59) -59(8-73)
= 73.8 − 73.59 − 59.8 + 59.73
= 8 73 − 59 + 59 −73 + 73
= 8.14 + 59.0
= 112
15 (4-7)- 15 (5-3)
=15. 4 − 7 − 5 − 3
= 15. 4 − 7 − 5 + 3
= 15. −5
= −75
25) 73(8-59) -59(8-73)
= 73.8 − 73.59 − 59.8 + 59.73
= 8 73 − 59 + 59 −73 + 73
1) thực hiện phép tính ( hợp lý nếu có thể )
a) 199(15-17)-199(-17+5)
b) 73(8-59)-59(8-73)
a) \(199\left(15-17\right)-199\left(-17+5\right)\)
\(=199.15-199.17+199.17-199.5\)
\(=199.\left(15-5\right)\)
\(=199.10=1990\)
b) \(73\left(8-59\right)-59\left(8-73\right)\)
\(=73.8-73.59-59.8+59.73\)
\(=8\left(73-59\right)\)
\(=8.14=112\)
Tính hợp lí:
73.(8-59)-59.(8-73)159.(18-59)-59.(18-159)-145.(13-57)+57.(10-145)17.(15-16)+16.(17-20)-38.(25-4)+35.(-4+38)23.(145-17)-145.(23-6)199.(15-17)-199.(-17+5)-39.(5-99)+99.(10-39)
1.73.(8-59)-59.(8-73)
=73.8-73.59-59.8-59.73
=73.(59-59)-8.(73-59)
=73.0-8.14
=0-112
=-112
2.159.(18-59)-59.(18 - 159)
=159.18-59.159-59.18-59.159
=159.(59-59)-18.(159-59)
=159.0-18.100
=0-1800
=-1800
1)thực hiện phép tinh ( hợp lí nếu có thể )
a) 73.(8-59) - 59.(8-73)
b)199.(15-17) - 199.( -17 + 5 )
a) \(73\left(8-59\right)-59\left(8-73\right)\)
\(=73.8-73.59-59.8+59.73\)
\(=8.\left(73-59\right)\)
\(=8.14=112\)
b) \(199\left(15-17\right)-199\left(-17+5\right)\)
\(=199.15-199.17+199.17-199.5\)
\(=199.\left(15-5\right)\)
\(=199.10=1990\)
a) 73.(8-59) - 59.(8-73)
= 73 . 8 - 73 . 59 - 59 . 8 + 59 . 73
= - 73 . 59 + 59 . 73 + 73 . 8 - 59 . 8
= 0 + 8 ( 73 - 59 )
= 8 . 14
= 112
b)199.(15-17) - 199.( -17 + 5 )
= 199 . 15 - 199 . 17 - 199 . (- 17 ) + ( - 199 ) . 5
= 199 . 15 - 19 . 17 + 199 . 17 + ( - 199 ) . 5
= 199 . 15 - 0 + 199 . ( - 5 )
= 199 . [ 15 - ( - 5 ) ]
= 199 . 10
= 1990
73(8-59)-15(5-3)
73.(8-59) -15.(5-3)
= 73 . (-51)-15.2
= [73.(-51) ] - (15.2)
= -3723 -30
=(-3753)
73.(8-59) -15.(5-3)
= 73 . (-51)-15.2
= [73.(-51) ] - (15.2)
= -3723 -30
= -3753
73(8-59)-15(5-3)
= 73.(-51)-15.2
= -3723-30
= -3753
Thực hiện phép tính :
a) 2014 + (-1999) + 1986 + 175 + (-2001)
b) 59 x 73 - 30^2 + 27 x 59
c) 128 - ( 68 + 8 x ( 37 - 35 )^2) : 4
a , 2014+(-1999)+1986+175+(-2001) = (2014+1986)+(-1999+-2001)+175
= 4000 + -4000 +175
= 175
roi tu lam nhe minh ban roi phai day
nice to meet you
tinh 1 cach hop li; a, -39.(5-99)+99.(10-39) b,153.177-153.77 c, 199.(15-17)-99.(-17+5) d, 73.(18-59)-59.(8-73)
a: =-39*5+39*99+99*10-99*39
=-39*5+99*10
=990-195=795
b: =153(177-77)=15300
c: =199*15-199*17+99*17-99*5
=17(-100)+199*15-99*5
=790
d: =73*18-73*59-59*8+59*73
=73*18-59*8
=842
X-7 = -5 (x+2) = 0 (3x - 24) . 73 =2.74 | x - 5 | = |-7| x- [42 + ( -28) = -8 ( 7x - x ) - ( 25+7 ) = -25 |x-3| = |5| + | -7 | ( x : 3-4 ) : 5 =15 | x -3 | = 7 - (-2) 128 -3 . (x+4) = 23 4 - ( 7-x ) = x - (13-4 ) BÀI 2 : TÍNH NHANH S1 = 1+2+3+.......999 S1= 10 +12 + 14 +.......2010 S3 + 21 + 23 + 25 + .......10001
TÌNH BẰNG CÁCH HỢP LÝ
a, 27x36 + 73 x 99 + 27 x 14 - 49 x 73 b, 21 x (271 + 29 ) + 79 x ( 271 + 29)
c, (4^5 x10 x 5^6 + 27^5 x 2^8) : (2^8 x 5^4 x 5^7 x 2^5)
giúp mik với
a, 27x 36 + 73 x 99 + 27 x 14 - 49 x 73
= 27 ( 36 + 14 ) + 73 ( 99 - 49 ) = 27 x 50 + 73 x 50
= 50 ( 27 + 73) = 50 x 100 = 5 000
b, 21 x (271 + 29 ) + 79 x ( 271 + 29)
= (271 + 29 ) ( 21 + 79)
= 300 x 100 = 30 000