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, thứ 4 là kiểm tra 90'p rồi
Bài 1:
a) 12.18 + 14.3 - 255 : 17
= 216 + 42 - 15
= 258 - 15
= 243
b) 15.8 - (83 - 30 + 17) - 144 : 6
= 15.8 - (53 + 17) - 144 : 6
= 15.8 - 70 - 144 : 6
= 120 - 70 - 144 : 6
= 120 - 70 - 24
= 50 - 24
= 26
c) 24.(15 + 30 + 85 - 120) : 10
= 24.(45 + 85 - 120) : 10
= 24.(130 - 120) : 10
= 24.10 : 10
= 24.1
= 24
d) 15 - 25.8 : (100.2)
= 15 - 25.8 : 200
= 15 - 200 : 200
= 15 - 1
= 14
e) 32.5 - 22.7 + 1.5
= 9.5 - 4.7 + 1.5
= 45 - 28 + 5
= 17 + 5
= 22
g) (24.5 - 52.2) : (5.2) - 3
= (24.5 - 25.2) : (5.2) - 3
= (120 - 50) : 10 - 3
= 70 : 10 - 3
= 7 - 3
= 4
h) [(52.23 - 72.2) : 2].6 - 7.25
= [(25.8 - 49.2) : 2].6 - 7.32
= [(200 - 98) : 2].6 - 224
= [102 : 2].6 -224
= 51.6 - 224
= 306 - 224
= 82
i) 27 : 22 + 54 : 53.24 - 3.25
= 25 + 5.24 - 3.25
= 32 + 5.16 - 3.32
= 32 + 80 - 96
= 112 - 96
= 16
k) (37.35) : 310 + 5.24 - 73 : 7
= 312 : 310 + 5.24 - 72
= 32 + 5.24 - 72
= 9 + 5.16 - 49
= 9 + 80 - 49
= 89 - 49
= 40
Bài 2:
a) 547 + 389 + 453 + 211
= (547 + 453) + (389 + 211)
= 1000 + 600
= 1600
b) 125.98.2.8.25
= (125.8).(25.2.98)
= 1000.4900
= 4900000
c) 8466.15 + 170.4233
= 4233.2.15 + 170.4233
= 4233.30 + 170.4233
= 4233.(30 + 170)
= 4233. 200
= 846600
d) (62007 - 62006) : 62006
= 62007 : 62006 - 62006 : 62006
= 6 - 1
= 5
e) (112003 + 112002) : 112002
= 112003 : 112002 + 112002 : 112002
= 11 + 1
= 12
f) 4.24.52 - (33.18 + 33.12)
= 4.24.25 - [33.(18 + 12)]
= 4.25.24 - [27.30]
= 100.24 - 810
= 2400 - 810
= 1590
g) 23.7.53- (52.65 + 52.35)
= 8.7.125 - (25.65 + 25.35)
= 8.125.7 - [25.(65 + 35)]
= 1000.7 - [25.100]
= 7000 - 2500
= 4500
Xin lỗi nha, nhìu quá mk lm ko hết, thông cảm cho mk.
a) (18+12.3):9-5
=(18+36):9-5
=54:9-5
=6-5
=1
b) 368+42:7-(23+3)
= 368+42:7-(8+3)
= 368+42:7-11
= 368+6-11
=374-11
=363
c) 324 :322+3.4+3560
=324-22+12+1
=32+12+1
=9+12+1
=21+2
=22
d) 210:25-75:25+3.3
=210-5-3+9
=25-3+9
=32-3+9
=29+9
=38
e) 1449-[(216+184):23].32
=1449-(400:8).9
=1449-50.9
=1449-450
=999
f) 600-400:[118.2-2(50.3-9.16)2]
=600-400:[118.2-2(150-144)2]
=600-400:(118.2-2.62)
=600-400:(118.2-2.36)
=600-400:(236-72)
=600-400:164
=600-100/41
=24500/41 (đề sai)
g) 2001.27+2001.63+2001.10
=2001.(27+63+10)
=2001.100
=200100
h) 64.54+47.64-64
=64.(54+47-1)
=64.100
=6400
i) (-17)+15+68+17+(-15)
=(-17+17)+(-15+15)+68
=0+0+68
=68
j) (-17)+|-5|+|10|+(-11)
= (-17)+5+10+(-11)
=-12+10+(-11)
=-2+(-11)
=-13
k) -75+(-9)+4
=-84+4
=-80
l) -100+(-15+10)+|(-48)+(-22)|
=-100+(-5)+|-70|
=-100+(-5)+70
=-105+70
=-35
a) (18+12.3):9-5
=(18+36):9-5
=54:9-5
=6-5
=1
b) 368+42:7-(23+3)
= 368+42:7-(26)
=368+6-64
=374-64
=310
c) 324 :322+3.4+3560
=32+12+1
=9+12+1
=21+1
=22
d) 210:25-75:25+3.3
=25-3+9
=32-3+9
=29+9
=38
e) 1449-[(216+184):23].32
= 1449-[400:8].9
=1449-50.9
=1449-450
=999
f) 600-400:[118.2-2(50.3-9.16)2]
=600-400:[118.2-2.(150-9.16)2]
=600-400:[118.2-2.(150-144)2]
=600-400:[118.2-2.62]
=600-400:[118.2-2.36]
=600-400:[236-72]
=600-400:164
=Đề sai nha bạn
g) 2001.27+2001.63+20010
=2001.(27+63)+20010
=2001.100+20010
=200100+20010
=220110
h) 64.54+47.64-64
=64.(54+47-1)
=64.(101-1)
=64.100
=6400
i) (-17)+115+68+17+(-15)
=98+68+17+(-15)
=166+17+(-15)
=183+(-15)
=168
j) (-17)+|-5-|+|10|+(-11)
=(-17)+5+10+(-11)
=(-12)+5+10+(-11)
=-7+10+(-11)
=3+(-11)
=-8
k) -75+|(-9)+4|
=-75+|-5|
=-75+5
=-70
l) -100+(-15+10)+|(-48)+(-22)|
= -100+(-15+10)+|-70|
= -100+(-15+10)+70
=-100+(-5)+70
=-105+70
=-35
a.17 . 85 + 25 . 17 + 1200
=17.(85+25)+1200
=17.110+1200
=1870+1200
=3070
b.62 : 4 . 3 + 2 . 52
=36:4.3+2.25
=27+50
=77
c.5 . 42 - 18 : 32
=5.16-18:9
=80-2
=78
d.3 . 52 - 16 : 23 + 34 : 33
=3.25-16:8+3
=75-2+3
=76
e.220 - [ 32 . 33 - ( 12 - 70 ) 2]
=220-35+112
=220-243+121
=98
j. 49 . 73 + 49 . 51 - 49 . 24
=49.(73+51-24)
=49.100
=4900
Con bấm mỏi suốt đấy mấy má
nhầm
a) 17 . 85 + 25 . 17 + 1200
=(17.85+25.17)+1200
=17(85+25)+1200
=17.110+1200
=1870+1200
=3070
b) 62 : 4 . 3 + 2 . 52
=36:4.3+2.25
=9.3+50
=27+50
=77
c) 5 . 42 - 18 : 32
=5.16-18:9
=80-2
=78
d) 3 . 52 - 16 : 23 + 34 : 33
=3.25-24:23+3(4-3)
=75-2(4-3)+31
=75-21+3
=75-2+3
=76
e) 220 - [ 32 . 33 - ( 12 - 70 ) 2 ]
=220-[3(2+3)-(12-1)2]
=220-(35-112)
=220-(243-121)
=220-122
=98
j) 49 . 73 + 49 . 51 - 49 . 24
=49(73+51-24)
=49.100
=4900
A, (-25). 21. (-2)2. (-|-3|). (-1)2015
B, (-5)3. 67. (-|-2|). (-1)2014
C, 35.18 – 5.7.28 + 35. (-90)
D, 24. (16 – 5) – 16. (24 – 5)
E, - 79. (73 – 27) – 73. (-79 + 27)
G, 31. (-18) + 31. (-8)-31
M, -48 + 48. (-78) + 48. (-21)
N, -|-17| + 2. [ 24: (-8) + (-5)2]
I, -|-7|. [(-2)4 + (-36): (-32)] – (-5)3
a) A = 1 + 3 + 32 + .... + 311
= (1+3+32 ) + ( 33 + 34 + 35) + ..... + (39 + 310 + 311)
= 13 + 33 . 13 + .... + 39 . 13
= 13 . (1+ 33 +....+ 39)
=> A chia hết cho 13
b) B = 165 + 215
= 220 +215
= 215 . 25 + 215
= 215 . ( 25 + 1)
= 215 .33
=> B chia hết cho 33
c) C= 5 + 52 + 53 + .....+ 58
= (5 + 52) + (53 + 54) +....+ ( 57 + 58)
= 30 + 52 (5 + 52) + ....+ 56 ( 5 + 52)
= 30 + 52 . 30 + .....+ 56 . 30
= 30. ( 1+ 52 +....+ 56 )
=> C chia hết cho 30
d) D= 45 + 99+ 180 chia hết cho 9
Do 45 chia hết cho 9
99 chia hết cho 9
180 chia hết cho 9
=> 45 + 99 + 180 chia hết cho 9
e) E = 1+ 3 + 32 + 33 + ......+ 3199
= (1+3+32) + (33 + 34 + 35) +......+ (3197 + 3198 + 3199)
= 13 + 33 (1+3+32) +.......+ 3197(1+3+32)
= 13 + 33 . 13 + ..... + 3197 .13
= 13. ( 1+ 33 +....+ 3197)
=> E chia hết cho 13
f)
Ta có: 1028 + 8 = 100...08 (27 chữ số 0)
Xét 008 chia hết cho 8 => 1028 + 8 chia hết cho 8 (1)
Mà 1+27.0+ 8 = 9 chia hết cho 9 => 1028 + 8 chia hết cho 9 (2)
Mà (8,9) =1 (3)
Từ (1); (2); (3) => 1028 + 8 chia hết cho (8.9)= 72
g)
ta có: G= 88 + 220 = (23)8 + 220 = 224 + 220 = 220 . 24 + 220 = 220 . (24 + 1) = 220 . 17
=> G chia hết cho 17
a) A = 1 + 3 + 3^2 + ... + 3^11
A = ( 1 + 3 + 3^2 ) + ... + ( 3^9 + 3^10 + 3^11 )
A = 1(1 + 3 + 3^2 ) + ... + 3^9 ( 1 + 3 + 3^2 )
A = 1 . 13 + ... + 3^9 . 13
A = 13 ( 1 + ... + 3^9 ) chia hết cho 13
còn mấy ý kia bạn chỉ cần tách nhóm rồi làm tương tự là ok
Good luck
2:
a: \(2^2\cdot3-4=4\cdot3-4=12-4=8\)
b: \(16-2^3\cdot2=16-2^4=16-16=0\)
c: \(4^2-4\cdot2=16-8=8\)
d: \(3^3-2\cdot3^2=27-2\cdot9=27-18=9\)
e: \(7^2-9\cdot2^2=49-9\cdot4=49-36=13\)
f: \(2^2\cdot3+4^2=4\cdot3+16=12+16=28\)
Bài 1:
a: \(13+21\cdot5-\left(198:11-8\right)\)
\(=13+105-18+8\)
=21+87
=108
b: \(272:16-5+4\cdot\left(30-5-255:17\right)\)
\(=17-5+4\cdot\left(30-5-15\right)\)
\(=12+4\cdot10=12+40=52\)
c: \(15\cdot24-14\cdot5\cdot\left(145:5-27\right)\)
\(=360-70\left(29-27\right)\)
=360-140
=220
d: \(18\cdot3-18\cdot2+3\cdot\left(\dfrac{51}{17}\right)\)
\(=18\left(3-2\right)+3\cdot3\)
=18+9
=27
e: \(64+115+36-25\cdot8\cdot6\cdot2^2\cdot3+4^2\)
\(=100+115-200\cdot6\cdot4\cdot3+16\)
\(=231-14400=-14169\)
f: \(15\cdot8-\left(17-30+83\right)-144:6\)
\(=120-24-\left(100-30\right)\)
=96-70
=26