Tính:
-43 + 61 - (-81 : 9) + 2 + 45 + 37 - (69 * 2) + 180
BT1: Tính nhanh:
1) 45 . ( 13 + 78 ) + 9 . ( 87 + 22 ) .5
2) 43 . 37 + 93 . 43 + 57 . 61 + 69 . 57
1)
\(45\left(13+78\right)+9\left(87+22\right)5\)
\(=45\left(13+78\right)+45\left(87+22\right)\)
\(=45\left(13+78+87+22\right)\)
\(=45\left[\left(87+13\right)+\left(78+22\right)\right]\)
\(=45\left[100+100\right]\)
\(=45.200\)
\(=9000\)
2)
\(43+37+93.43+57.61+69.57\)
\(=43\left(37+93\right)+57.\left(61+69\right)\)
\(=43.130+57.130\)
\(=130\left(43+57\right)\)
\(=130.100\)
=13000
2 . 53 . 27 + 6 . 9 . 87 - 3 . 18 . 40 = ???
12 . 25 + 29 . 25 + 59 . 25 = ???
43 . 37 + 93 . 43 + 57 . 61 + 69 . 57 = ???
12 . 53 + 53 . 172 - 53 = ???
35 . 54 + 35 . 58 + 65 . 75 + 65 . 45 = ???
39 . 8 + 70 . 3 + 31 . 8 = ???
2 . 53 . 27 + 6 . 9 . 87 - 3 . 18 . 40
= 2. 53 . 9 . 3 + 2. 3 .9 .87 - 3 .2 .9 .40
= 54.53+54.87-54.40
=54(53+87-40)
=54. 100=5400
12 . 25 + 29 . 25 + 59 . 25
= 25 . ( 12+29+59)
=25 . 90
=2250
43 . 37 + 93 . 43 + 57 . 61 + 69 . 57
= 43.(37+93)+57(61+69)
=43.130+57.130
=130.(43+57)
=130.100
=13 000
12 . 53 + 53 . 172 - 53
=53(12+172-1)
=53.184
=9752
35 . 54 + 35 . 58 + 65 . 75 + 65 . 45
=35(54+58)+65(75+45)
=35.112+65.120
=3920+7800
=11720
39 . 8 + 70 . 3 + 31 . 8
=8(39+31)+70.3
=8.70+70.3
=70.(8+3)
=70.11
=770
2 . 53 . 27 + 6 . 9 . 87 - 3 . 18 . 40
= ( 2 . 27 ) . 53 + ( 6 . 9 ) . 87 - ( 3 . 18 ) . 40
= 54 . 53 + 54 . 87 - 54 . 40
= 54(53+87-40)
= 5400
12 . 25 + 29 . 25 + 59 . 25
= 25( 12 + 29 + 59 )
= 2500
43 . 37 + 93 . 43 + 57 . 61 + 69 . 57
= 43( 37 + 93 ) + 57(61 + 69 )
= 5590 + 7410
= 13000
12 . 53 + 53 . 172 - 53
= 53( 12 + 172 ) - 53
= 9752 - 53
= 9699
35 . 54 + 35 . 58 + 65 . 75 + 65 . 45
= 35( 54 + 58 ) + 65( 75 + 45 )
= 3920 + 7800
= 11720
1) Tính nhanh :
a) 8 x 17 x 125
c) 4 x 37 x 25
d) 43 x 27 + 93 x 43 + 57 x 81 + 69 x 57
e) 123456789 x 45 biết 12345679 x 9 = 111 111 111
7 x 17 x 125 = (8 x 125) x 17 = 1000 x 17 = 17000
4 x 37 x 25 = (25 x 4 ) x 7 = 100 x 7 = 700
43 x 27 + 93 x 43 + 57 x 81 + 69 x 57 = 43 x (27 + 93) + 57 x (81 +69) = 43 x 120 + 57 x 120 + 57x30 = 120 x (43 + 57) + 1710 = 12000 + 1710 = 13710
Tính hợp lý ( nếu có thể)
43*37+93*43+57*61+69*5
=43.37+93.43+57.61+69.57
=43.(37+93)+57.(61+69)
=43.130+77.130
=130.(43+57)
=13000
Tính nhanh
45×37+93×45+55×61+69×55
`#3107.101107`
\(45\times37+93\times45+55\times61+69\times55\)
\(=45\times\left(37+93\right)+55\times\left(61+69\right)\)
\(=45\times130+55\times130\)
\(=130\times\left(45+55\right)\)
\(=130\times100\)
\(=13000\)
\(#GNamK\)
45x37+93x45+55x61+69x55
=45x(37+93)+55x(61+69)
=45x130+55x130
=130x(45+55)
=130x100=13000
43x37+93x43+57x61+69x57=13000
1300
ai bấm sai thì cứ bấm
nhưng mình đúng thì vẫn là thật
X:2+250*4=55*61+69*55-45*37-93*45
\(x:2+250.4=55.61+69.55-45.37-93.45\)
\(\Leftrightarrow x:2+1000=55\left(61+69\right)-45\left(37+93\right)\)
\(\Leftrightarrow x:2+1000=55.130-45.130\)
\(\Leftrightarrow x:2+1000=130\left(55-45\right)\)
\(\Leftrightarrow x:2+1000=130.10\)
\(\Leftrightarrow x:2+1000=1300\)
\(\Leftrightarrow x:2=1300-1000=300\)
\(\Leftrightarrow x=300.2=600\)
Vậy \(x=600\)
X:2+250*4=55*61+69*55-45*37-93*45
X:2+250*4=(55*61+69*55)-(45*37+93*45)
X:2+1000=55*(61+69)-45*(37+93)
X:2+1000=55*130-45*130
X:2+1000=(55-45)*130
X:2+1000=10*130
X:2+1000=1300
X:2=1300-1000
X:2=300
X=300*2
X=600
Vậy X = 600
1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20+21+22+23+24+25+26+27+28+29+30+31+32+33+34+35+36+37+38+39+40+41+42+43+44+45+46+47+48+49+50+51+52+53+54+56+57+58+59+60+61+62+63+64+65+66+67+68+69+70=?
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