TÍNH NHANH
a) 58.75+58.50-58.25
b)27.39+27.63-2.27
c)128.46+128.32+128.22
Tính nhanh:
A) 58.75+58.50-58.25
B) 27.39+27.63-2.27
C) 128.46+128.32+128.22
D) 12.35+35.182-35.94
E) 48.19+48.115+134.52
F) 136.23+136.17-40.36
G) 17.93+116.83+17.23
H) 19.27+47.81+19.20
I) 87.23+13.93+70.87
Áp dụng công thức này là được :
m.a+m.b+m.c = m(a+b+c)
a) 58.75 + 58.50 - 58.25
= 58. (75 + 50 - 25)
= 58. 100
= 5800
b) 27.39 + 27.63 + 2.27
= 27. (39 + 63 - 2)
= 27. 100
= 2700
c) 128.46 + 128.32 + 128.22
= 128.(46 + 32 + 22)
= 128. 100
= 12800
d) 12.35 + 35.182 - 35.94
= 35.(12 + 182 - 94)
= 35. 100
= 3500
e) 48.19 + 48.115 + 134.52
= 48.(19 + 115) + 134.52
= 48.134 + 134.52
= 134.(48 + 52)
= 134.100
= 13400
f) 136.23 + 136.17 - 40.36
= 136.(23 + 17) - 40.36
= 136.40 - 40.36
= 40.(136 - 36)
= 40.100
= 4000
g) 17.93 + 116.83 + 17.23
= 17.(93 + 23) + 116.83
= 17.116 + 116.83
= 116.(17 + 83)
= 116.100
= 11600
h) 19.27 + 47.81 + 19.20
= 19.(27 + 20) + 47.81
= 19.47 + 47.81
= 47.(19 + 81)
= 47.100
= 4700
i) 87.23 + 13.93 + 70.87
= 87.(23 + 70) + 13.93
= 87.93 + 13.93
= 93.(87 + 13)
= 93.100
= 9300
#NgHn
A) 58.75+58.50-58.25
B) 27.39+27.63-2.27
C) 128.46+128.32+128.22
D) 12.35+35.182-35.94
E) 48.19+48.115+134.52
F) 136.23+136.17-40.36
G) 17.93+116.83+17.23
H) 19.27+47.81+19.20
I) 87.23+13.93+70.87
a,
58.75 + 58.50 - 58.25
= 58.(75 + 50 - 25)
= 58. (125 - 25)
= 58.100
= 5800
b, 27.39 + 27.63 - 2.27
= 27.(39 + 63 - 2)
= 27.(102 - 2)
= 27.100
= 2700
c, 128.46 + 128.32 + 128.22
= 128.(46 + 32 + 22)
= 128.(78 + 22)
= 128.100
= 12800
a) 58.75 + 58.50 – 58.25.34
b) 27.39 + 27.63 – 2.27a)
c) 128.46 + 128.32 + 128.22
d) 66.25 + 5.66 + 66.14 + 33.66
e) 12.35 + 35.182 – 35.94
2. Tính nhanh
a,58.75 + 58.50 - 58.25 e,48.19 + 48.115+134.5
b,27.39 + 27.63 - 2.27 f,125.98 - 125.46 - 52.25
c,128.46 + 128.32 + 128.22 g,136.23 + 136.17 - 40.36
d,66.25 + 5.66 + 66.14+ 33.66 h,1+2+3+4+5+...+n
i,2+5+11+...+47+65
a,58.75 + 58.50 - 58.25
= 58.(75 + 50 - 25)
= 58.100
= 5800
b,27.39 + 27.63 - 2.27
= 27.(39 + 63 - 2)
= 27.100
= 2700
c,128.46 + 128.32 + 128.22
= 128.(46 + 32 + 22)
= 128.100
= 12800
d,66.25 + 5.66 + 66.14+ 33.66
= 66.(25 + 5 + 14 + 33)
= 66.77
= 5082
i,2+5+11+...+47+65
= 2+5+11+23+47+65
= (65+5) + (23+47) + (2+11)
= 70 + 70 + 13
= 70.2 + 13
= 140 + 13
= 153
e,48.19 + 48.115+134.5
= 48.(19 + 115) + 134.5
= 48.134 + 134.5
= 134.(48 + 5)
= 134.53
=7102
f,125.98 - 125.46 - 52.25
= 125.(98 - 46) - 52.25
= 125.52 - 52.25
= 52.(125 - 25)
= 52.100
= 5200
g,136.23 + 136.17 - 40.36
= 136.(23 + 17) - 40.36
= 136.40 - 40.36
= 40.(136 - 36)
= 40.100
= 4000
h,1+2+3+4+5+...+n
\(=\frac{n\left(n+1\right)}{2}\)
2 . Tính nhanh
a) 58. 75 + 58 . 50 - 58 . 25
= 58 . ( 75 + 50 - 25 )
= 58 . 100
= 5 800
b) 27 . 39 + 27 . 63 - 2 . 27
= 27 . ( 39 + 63 - 2 )
= 27 . 100
= 2 700
c) 128 . 46 + 128 . 32 + 128 . 22
= 128 . ( 46 + 32 + 22 )
= 128 . 100
= 12 800
d) 66 . 25 + 5 . 66 + 66 . 14 + 33 . 66
= 66 . ( 25 + 5 + 14 + 33 )
= 66 . 77
= 5082
e) 48 . 19 + 48 . 115 + 134 . 5
= 48 . ( 19 + 115 ) + 134 . 5
= 48 . 134 + 134 . 5
= 134 . ( 48 + 5 )
= 134 . 53
= 7102
f, 125 . 98 - 125 . 46 - 52 . 25
= 125 . ( 98 - 46 ) - 52 . 25
= 125 . 52 - 52 . 25
= 52 . ( 125 - 25 )
= 52 . 100
= 5 200
g, 136 . 23 + 136 . 17 - 40 . 36
= 136 . ( 23 + 17 ) - 40 . 36
= 136 . 40 - 40 . 36
= 40 . ( 136 - 36 )
= 40 . 100
= 4 000
\(a.58.75+58.50+58.25\)
\(=58.\left(75+50-25\right)\)
\(=58.100\)
\(=5800\)
\(b.27.39+27.63-2.27\)
\(=27.\left(39+63-2\right)\)
\(=27.100\)
\(c.128.46+128.32+128.22\)
\(=128.\left(46+32+22\right)\)
\(=128.100=12800\)
\(d.66.25+5.66+66.14+33.66\)
\(=66.\left(25+5+14+66\right)\)
\(=66.110=7260\)
Bài 1:Tìm x
a,(3.x-2^4).7^3=2.7^4
b,x-[ 42+(-28)] = -8
c,4-(7.x)=x-(13-4)
Bài 2:Tính nhanh
a,58.75+58.50-58.25
b,27.39+27.63-2.27
c,48.13+48.115+134.52
d,27.121-87.27+73.34
Bài 1
a) (3x - 2⁴).7³ = 2.7⁴
3x - 16 = 2.7⁴ : 7³
3x - 16 = 2.7
3x - 16 = 14
3x = 14 + 16
3x =30
x = 30 : 3
x = 10
b) x - [42 + (-28)] = -8
x - 14 = -8
x = -8 + 14
x = 6
c) 4 - 7.x = x - (13 - 4)
x + 7x = 4 + 9
8x = 13
x = 13/8
Bài 1: a, (3\(x\) - 24 ).73 = 2.74
3\(x\) - 24 = 2.74 : 73
3\(x\) - 16 = 14
3\(x\) = 30
\(x\) = 10
b, \(x\) - (42 + (-28) ] = -8
\(x\) - 14 = -8
\(x\) = 14 - 8
\(x\) = 6
c, 4 - (7\(x\)) = \(x\) - (13 - 4)
4 - 7\(x\) = \(x\) - 9
\(x\) + 7\(x\) = 4 + 9
8\(x\) = 13
\(x\) = \(\dfrac{13}{8}\)
Bài 2
a) 58.75 + 58.50 - 58.25
= 58.(75 + 50 - 25)
= 58.100
= 5800
b) 27.39 + 27.63 - 2.27
= 27.(39 + 63 - 2)
= 27.100
= 2700
c) 48.13 + 48.115 + 134.52
= 48.(13 + 115) + 134.52
= 48.128 + 134.52
= 6144 + 6968
= 13112
d) 27.121 - 87.27 + 73.34
= 27.(121 - 87) + 73.34
= 27.34 + 73.34
= 34.(27 + 73)
= 27.100
= 2700
tính nhanh các phép tinh:
A=8.17.125
b=4.37.25
c= 58.75+58.50-5825
d=27.39+27.63-2.27
\(A=8\cdot17\cdot125=\left(125\cdot8\right)\cdot17=1000\cdot17=17000\)
\(B=\left(25\cdot4\right)\cdot37=100\cdot37=3700\)
\(C=\left(75+50-25\right)\cdot58=100\cdot58=5800\)
\(D=\left(39+63-2\right)\cdot27=100\cdot27=2700\)
A=8.17.125= (8.125).17= 1000.17=17000
b=4.37.25=(4.25).37=100.37=3700
c= 58.75+58.50-58.25= 58.(75+50 - 25)= 58.100=5800
d=27.39+27.63-2.27= 27.(39+63-2)=27.100=2700
1. Tính nhanh
a) 58.75+58.50-58.25 e)48.19+48.114+134.52
b) 128.35+128.32+ 128.22. f) 27.121-87.27+73.34
c) 12.35+53.182-35.94 g) 125.98-125.46-52.25
Bài 1: Tính giá trị của biểu thức sau:
a) 2763 + 152 b) (-7) + (-14) c) (-35) + (-9)
d) (-5) + (-248) e) (-23) + 105 f) 78 + (-123)
g) 23 + (-13) h) (-23) + 13 i) 26 + (-6)
k) 19 + (23 – 33) m) (-12 – 44) + (-3) n) 4 – (-15)
o) 99 – [109 + (-9)] p) (-75) + 50
q (-75) + (-50) r) (-23) + 13 + ( - 17) + 57
s) 14 + 6 + (-9) + (-14)
Bài 2: Tính nhanh:
a) 58.75 + 58.50 – 58.25 b) 27.39 + 27.63 – 2.27
c) 128.46 + 128.32 + 128.22 d) 66.25 + 5.66 + 66.14 + 33.66
e) 12.35 + 35.182 – 35.94 g) 27.121 – 87.27 + 73.34
h) 125.98 – 125.46 – 52.25 i) 136.23 + 136.17 – 40.36
Bài 3: Tìm số nguyên x, biết:
a) x - 7 = -5 b) 128 - 3 . ( x+4) = 23
c) [ (6x - 39) : 7 ] . 4 = 12 d)( x: 3 - 4) . 5 = 15
Bài 4: Tìm tổng của tất cả các số nguyên thỏa mãn:
a) -4 < x < 3 b) -5 < x < 5
c) -10 < x < 6 d) -1 ≤ x ≤ 4
e) -6 < x ≤ 4 f) -4 < x < 4
128.46+128.32+128.22
128.46 + 128.32 + 128.22
=128.(46+32+22)
=128.100=12800
K mk nha, mk k lại
128.46+128.32+128.22=128.(46+32+22)
=128.100
=12800
SỐ ĐÓ LÀ
12800
AI K MÌNH
MÌNH K LẠI CHO