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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
\(27.332+93.43+57.61+69.57\\ =27.332+93.43+57.\left(61+69\right)\\ =27.332+93.43+57.130\\ =8964+3999+7410=20373\\ 34.75+75.66-65.100\\ =\left(34+66\right).75-65.100\\ =100.75-65.100\\ =100.\left(75-65\right)\\ =100.10=1000\\ \left(456.11+912\right).37:13:74\\ =5928:13:\left(74:37\right)\\ =456:2=228\\ 6^2:4.3+2.5^2\\ =36:4.3+2.25\\ =9.3+50=27+50=77\\ 5.4^2-18:3^2\\ =5.16-18:9\\ =80-2=78\\\left[\left(315+372\right).3+\left(372+315\right).7\right]:\left(26.13+74.14\right)\\ =687.\left(3+7\right):\left(338+1036\right)\\ 687.10:1374\\ =6870:1374=5\\ 12:\left\{390:\left[500-\left(125+35.7\right)\right]\right\}\\ =12:\left[390:\left(500-370\right)\right]\\ =12:\left(390:130\right)=12:3=4\\ 192000-\left(1500.2+1800.3+1800.2:3\right)\\ =192000-\left(3000+5400+1200\right)\\ =192000-9600=182400\)
a . 25 − 58 − 9 = - 31 b . 1 − ( 26 + 3 ) = - 28 c . 12.15 − 12.5 = 120 d . 10 − [ 12 − ( − 9 − 1 ) ] = -12 e . ( 38 − 29 + 43 ) − ( 43 + 38 ) = - 29 f . 2575 + 37 − 2576 − 29 = 7
a) − 105 + − 25 + ( − 105 ) + 50
= 105 + 25 + ( - 105) + 50
= [105 + ( -105)] + ( 25 + 50 )
= 0 + 75 = 75
b) 465 + − 38 + − 465 − 12 − − 42
= 465 + ( - 38) + ( -465) – 12 – 42
= [ 465 + (- 465) ] – ( 12 + 42 )
= 0 – 54 = 0 + ( -54 ) = -54
c) 65. − 19 + − 19 .24 + − 19 .11
= ( - 19) . ( 65 + 24 + 11 )
= ( -19) . 100 = -1900
d) − 3 2 + 2 3 − − 5 2 + 4 3
= 9 + 8 – 25 + 64 = 56
A có (99-17)+1=83 phần tử
Số ở giữa sẽ là 17+(82/2) = 58
Những số khác tạo thành các cặp
A=(17+99) + (18+98)+...+58
A=116*(82/2)+58= 4814
Những bài khác tương tự
a, 2 17 + 17 2 9 15 - 3 15 2 4 - 4 2
= 2 17 + 17 2 9 15 - 3 15 16 - 16
= 2 17 + 17 2 9 15 - 3 15 . 0
= 0
b, 1 2 + 2 3 + 3 4 + 4 5 . ( 1 3 + 2 3 + 3 3 + 4 3 ) ( 3 8 - 81 2 )
= 1 2 + 2 3 + 3 4 + 4 5 . ( 1 3 + 2 3 + 3 3 + 4 3 ) ( 3 4 . 2 - 81 2 )
= 1 2 + 2 3 + 3 4 + 4 5 . ( 1 3 + 2 3 + 3 3 + 4 3 ) ( 81 2 - 81 2 )
= 1 2 + 2 3 + 3 4 + 4 5 . ( 1 3 + 2 3 + 3 3 + 4 3 ) . 0
= 0
c, 7 24 + 7 23 : 7 22
= 7 24 : 7 22 + 7 23 : 7 22
= 7 24 - 22 + 7 23 - 22
= 7 2 + 7 1
= 49 + 7 = 56
b) 32, 33, 34 , 35.
\(a,2^2=4,2^3=8,2^4=16,2^5=32,2^6=64,2^7=128,2^8=256,2^9=512,2^{10}=1024\)
\(b,3^2=9,3^3=27,3^4=81,3^5=243\)
\(c,4^2=16,4^3=64,4^4=256\)
\(d,5^2=25,5^3=125,5^4=625\)
Ai trả lời nhanh mình k cho !!!!! ^-^