1 x 34 x 24 =
4 x 35 x 35 =
tính nhanh:
a, 123 x 56 + 100 x 44 - 56 x 123
b, 35 x 34 + 35 x 38 +70 x 83 + 70 x 81
c, 2 + 4 + 6 + 8 +......24
123 x 56 + 100 x 44 - 56 x 123
= 100 x 44
= 4400
2 + 4 + 6 + 8 + .... + 24 có số số hạng là:
(24 - 2) : 2 + 1 = 12 (số)
tổng là :
(24 + 2) x 12 : 2 = 156
123 x 56 + 100 x 44 - 56 x 123
= 100 x 44
= 4400
2 + 4 + 6 + 8 + .... + 24 có số số hạng là:
(24 - 2) : 2 + 1 = 12 (số)
tổng là :
(24 + 2) x 12 : 2 = 156
1.tính nhanh
a) 2 x 16 x 50 x 25
b) 35 x 24 + 35 x 76 + 55 x 19 + 55 x 81
c) 6 x 25 x 4 + 4 x 19 x 6 - 2 x 14 x 12
d) 19 x 64 + 76 x 34
e) 864 x 48 - 432 x 96 / 864 x 48 x 432
b) 35 x 24 + 35 x 76 +55 x 19 +55 x 91
= 35 x ( 24 + 76 ) + 55 x ( 19 + 91 )
= 35 x100 +55 x 100
= 100 x ( 55 + 35 )
= 90 x 100 =9 000
c) \(6\cdot25\cdot4+4\cdot19\cdot6-2\cdot14\cdot12\)
\(=24\cdot25+24\cdot19-24\cdot14\)
\(=24\left(25+19-14\right)\)
\(=24\cdot30=720\)
d) \(19\cdot64+76\cdot34\)
\(=76\cdot19+76\cdot34\)
\(=76\left(19+34\right)=76\cdot53=4028\)
a) 2 x 16 x 50 x 25
= ( 2 x 50 ) x ( 16 x 25 )
= 100 x 400
= 40 000
số 1 tính nhanh A 78 x 31 78 x 24 78 x 17 22 x 72C 53 x 39 47 x 39 53 x 21 47 x 21B 35 x 34 35 x 86 65 x 75 65 x 45D 27 x 332 68 x 27 73 x 332 68 x 73E 2 x 53 x 12 4 x 6 x 37 2 x 38 x 12F 3 x25 x 8 4 x 6 x 37 2 x 38 x 12
Tính nhanh :
a/ 320 x 63 - 16 x 20 + 32 x 370
b/ 35 x 61 + 215 x 5 + 35 x 39 + 57 x 25
c/ 34 x 24 - 94 x 6 + 83 x 48 - 47 x 88
a) 320 x 63 - 16 x 20 + 32 x 370
= 320 x 63 - 320 x + 320 x 37
= 320 x ( 63 - 1 + 37 )
= 320 x 99
= 320 x ( 100 - 1 )
= 320 x 100 - 320
= 32000 - 320 = 31 680
b) 35 x 61 + 215 x 5 + 35 x 39 + 57 x 25
= 5 x 427 + 5 x 215 + 5 x 273 + 5 x 285
= 5 x ( 427 + 215 + 273 + 285 )
= 5 x 1200 = 6000
c) 34 x 24 - 94 x 6 + 83 x 48 - 47 x 88
= 204 x 4 - 4 x 141 + 996 x 4 - 1034 x 4
= 4 x ( 204 - 141 + 996 - 1034 )
= 4 x 25 = 100
Tìm x thuộc Z,biết:
a)(71+x)-(-24-x)+(-35-x)=0
b)x-34-[(15+x)-(23-x)]=0
a) (71+x)-(-24-x)+(-35-x)=0 b)x-34-[(15+x)-(23-x)]=0
71+x+24+x+-35-x =0 x-34-15-x-23+x =0
(x+x-x)+(71+24-35) =0 (x-x+x)+(-34-15-23) =0
x+60 =0 x+-72 =0
x =0-60 x =0-(-72)
x = -60 x = 72
3 x 125 x 8 + 4 x 24 x 35 + 4 x 35 x 2 x 12
3 x 125 x 8 + 4 x 24 x 35 + 4 x 35 x 2 x 12
= 375 x 8 + 96 x 35 + 140 x 24
= 3000 + 3360 + 3360
= 3000 + 3360 x 2
= 3000 + 6720
= 9720
rút gọn
a.A= (71+x) - (-24-x) + (-35-x)
b.B=x-34-[(15+x) - (23-x)] c.C=(-15+|x|) + (25-|-x|)
mk chỉ làm ý A thui nha
\(A=\left(71+x\right)-\left(-24-x\right)+\left(-35-x\right)\)
\(A=71+x+24+x+\left(-35\right)-x\)
\(A=\left[71+24+\left(-35\right)\right]+\left(x+x-x\right)\)
\(A=60+x\)
Vậy \(A=60+x\)
\(a,A=\left(71+x\right)-\left(-24-x\right)+\left(-35-x\right)\)
\(=71+x+24+x-35-x\)
\(=60+x\)
\(b,B=x-34-\left[\left(15+x\right)-\left(23-x\right)\right]\)
\(=x-34-\left(15+x-23+x\right)\)
\(=x-34-15-x+23-x\)
\(=-x-26\)
a) A = (71 + x) - (-24 - x) + (-35 - x)
A = 71 + x + 24 + x + (-35) - x
A = (x + x - x) + (71 + 24 + (-35)
A = x + 60
b) B = x - 34 - [(15 + x) - (23 - x)]
B = x - 34 - [15 + x - 23 + x]
B = x - 34 - 15 - x + 23 - x
B = (x - x - x) + (-34 - 15 + 23)
B = -x + (-26)
c) C = (-15 + |x|) + (25 - |-x|)
C = (-15) + x + 25 - (-x)
C = (-15) + x + 25 + x
C = (x + x) + [(-15) + 25]
C = 2x + 10
4,Tìm x
A, x/36 = 24/32 b,71 - (33 + x ) = 26
C, 3,5 × x + 1,5 × x = 10
5,
Tính bằng cách hợp lý :
A, 4,63 × 7,8 + 7,8 + 7,8 × 4,32
B, 35 × 34 + 35 × 86 + 65 × 75 + 65 × 45
4a) \(\frac{x}{36}=\frac{3}{4}\)
\(\Rightarrow\frac{x}{36}=\frac{27}{36}\)
\(\Rightarrow x=27\)
4b) 33 + x = 71 - 26
33 + x = 45
x = 45 - 33
x = 12
4c) x * (3,5 + 1,5) = 10
x * 5 = 10
x = 10 ; 5 = 2
4,
\(a,\frac{x}{36}=\frac{24}{32}\)
\(=>\frac{x}{36}=\frac{3}{4}=\frac{27}{36}\)
\(=>x=27\)
\(b,71-\left(33+x\right)=26\)
\(=>-\left(33+x\right)=26-71=-45\)
\(=>33+x=45\)
\(=>x=12\)
\(c,3,5\cdot x+1,5\cdot x=10\)
\(>x\cdot\left(3,5+1,5\right)=10\)
\(=>x\cdot5=10\)
\(=>x=2\)
. là nhân nha
4.
a) x/36 = 24/32
24/32 = 3/4 = 27/36
=> x = 27
b) 71 - ( 33 + x ) = 26
33 + x = 71 - 26
33 + x = 45
x = 45 - 33
x = 12
c) 3, 5 . X + 1, 5 . x = 10
x( 3, 5 + 1, 5 ) = 10
x . 5 = 10
x = 10 : 5
x = 2
5.
a) 4, 63 . 7, 8 + 7, 8 + 7, 8 . 4, 32
= 7, 8. ( 4, 63 + 4, 32 + 1 )
= 7, 8 . 9, 95
= 77, 61
b) 35 . 34 + 35 . 86 + 65 . 75 + 65 . 45
= 35( 34 + 86 ) + 65( 75 . 45 )
= 35 . 120 + 65 . 120
= 120 . ( 35 + 65 )
= 120 . 100
= 12 000
Rút gọn các biểu thức sau:
a) M=(71+x)-(-24+x)+(-35-x)
b) N=x-34-[(15+x)-(23-x)]
a/ M = (71+x)-(-24+x)+(-35-x) = 71 + x + 24 - x - 35 - x = (71 + 24 - 35) - x = 95 - 35 - x = 60 - x
b/ N=x-34-[(15+x)-(23-x)] = x - 34 - (15 + x - 23 + x) = x - 34 - (-8 + 2x) = x - 34 + 8 - 2x = -26 - x
\(a,M=\left(71+x\right)-\left(-24+x\right)+\left(-35-x\right)\)
\(=71+x+24-x-35-x\)
\(=60-x\)
\(b,N=x-34-\left[\left(15+x\right)-\left(23-x\right)\right]\)
\(=x-34-\left(15+x-23+x\right)\)
\(=x-34-15-x+23-x\)
\(=-26-x\)
a) M=(71+x)-(-24+x)+(-35-x)
= 71+x-(-24)-x+(-35)-x
= (-24+71)+(-35)+(x-x-x)
= 47+(-35)+(-x)
= 12+(-x)
= 12-x
Vậy M=12-x