a x 34 + a x 65 + a = 6574,5
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Tính nhanh
a) 2017 x 34 + 2017 x 65 + 2017
b) 3/5 x 7/9 - 3/5 x 2/9
a) 2017 x 34 + 2017 x 65 + 2017
= 2017 x ( 34+65+1)
= 2017 x 100
= 201700
b) 3/5 x 7/9 - 3/5 x 2/9
= 3/5 x ( 7/9- 2/9)
= 3/5 x 5/9
= 1/3
a) 2017 x 34 + 2017 x 65 + 2017
= 2017 x (34 + 65 + 1)
= 2017 x 100
= 201700
b) \(\dfrac{3}{5}\) x \(\dfrac{7}{9}\) - \(\dfrac{3}{5}\) x \(\dfrac{2}{9}\)
= \(\dfrac{3}{5}\) x \(\left(\dfrac{7}{9}-\dfrac{2}{9}\right)\)
= \(\dfrac{3}{5}\) x \(\dfrac{5}{9}\)
= \(\dfrac{1}{3}\)
\(a,=2017\times\left(34+65+1\right)=2017\times100=201700\)
\(b,\dfrac{3}{5}\times\left(\dfrac{7}{9}-\dfrac{2}{9}\right)=\dfrac{3}{5}\times\dfrac{5}{9}=\dfrac{15}{45}=\dfrac{1}{3}\)
a) Tính bằng cách hợp lí nhất :
35 . 34 + 35 . 38 + 65 . 75 + 65 . 45 + 35 . 34
3 . 25 . 8 + 4 . 37 . 6 + 2 . 38 . 12
b) Tìm số tự nhiên x, biết :
( x - 5 ) ( x + 7 ) = 0
35 . 34 + 35 . 38 + 65 . 75 + 65 . 45 + 35 . 34 =
= 35 . 34 + 35 . 38 + 35 . 34 + 65 . 75 + 65 . 45
= 35 . ( 34 + 38 + 34 ) + 65 . ( 75 + 45 )
= 35 . 110 + 65 . 110
= 110 . ( 35 + 65 )
= 110 . 100
= 11000
Hok tốt!!!!!!!!!!!!!
a) Tính bằng cách hợp lí nhất :
35 . 34 + 35 . 38 + 65 . 75 + 65 . 45 + 35 . 34
= 35 . 34 + 35 . 38 + 35 . 34 + 65 . 75 + 65 . 45
= 35 . ( 34 + 38 + 34 ) + 65 . ( 75 + 45 )
= 35 . 106 + 65 . 120
= 3710 + 7800
= 11510
3 . 25 . 8 + 4 . 37 . 6 + 2 . 38 . 12
= 3 . 8 . 25 + 4 . 6 . 37 + 2 . 12 . 38
= 24 . 25 + 24 . 37 + 24 . 38
= 24 . ( 25 + 37 + 38 )
= 24 . 100
= 2400
b) Tìm số tự nhiên x, biết :
( x - 5 ) ( x + 7 ) = 0
\(\Rightarrow\orbr{\begin{cases}x-5=0\\x+7=0\end{cases}\Rightarrow\orbr{\begin{cases}x=5\\x=-7\end{cases}}}.\)
Vậy .......
3 . 25 . 8 + 4 . 37 . 6 + 2 . 38 . 12 =
= 3 . 8 . 25 + 4 . 6 . 37 + 2 . 12 . 38
= 24 . 25 + 24 . 37 + 24 . 38
= 24 . ( 25 + 37 + 38 )
= 24 . 100
= 2400
Hok tốt!!!!!!!!!!!
Tính bằng cách thuận tiện :
a) 456 x 65 + 456 x 34 + 456
b) 962 x 115 - 962 x 16 + 962
a,456*65+456*34+456
=456*65+456*34+456*1
=456*(65+34+1)
=456*100
=45600
a) = 456 x ( 65 + 34 + 1 )
= 456 x 100
= 45600
a ) 456 x 65 + 456 x 34 + 456
= 456 x 65 + 456 x 34 + 456 + 1
= 456 x ( 65 + 34 + 1 )
= 456 x 100
= 45600
b ) hong bít
Mik làm theo suy nghĩ nên k đúng hay sai cx đc nhen :))
2/ Tính bằng cách thuận tiện nhất:
a. 34, 65 + 21,78 + 65,35 + 78, 22
b. 4,5 x 5,5 + 4,7 x 4,5
c. 7,5 x 2,5 x 4
`34, 65 + 21,78 + 65,35 + 78, 22 `
`= (34, 65 +65,35 ) + ( 21,78 +78, 22 ) `
`= 100 + 100`
`= 200`
`b. 4,5 xx 5,5 + 4,7 xx 4,5 `
`= 4,5 xx ( 5,5 + 4,7 ) `
`= 4,5 xx 10,2`
`= 45,9`
`c. 7,5 xx 2,5 xx 4 `
`= 7,5 xx ( 2,5 xx 4 ) `
`= 7,5 xx 10`
`=75`
`34,65+21,78+65,35+78,22`
`=(34,65+65,35)+(21,78+78,22)`
`=100+100=200`
`b)4,5xx5,5+4,7xx4,5`
`=4,5xx(5,5+4,7)`
`=4,5xx10,2`
`=4,5xx(10+0,2)`
`=4,5xx10+4,5xx0,2`
`=45+0,9=45,9`
`c)7,25xx2,5xx4`
`=7,25xx(2,5xx4)`
`=7,25xx10=72,5`
Bài 3 Tính nhanh
a, 35 x 34 + 35 x 38 + 65 x 72 + 65 x 72
b, 3 x 25 x 8 + 4 x 37 x 6 + 2 x 38 x12
Các bạn nhớ trình bày giúp mình nhé *.*
a)=35x(34+38)+72x(65+65)
=35x72+72x130
=72x(35+130)
=72x165
=11880
tính nhanh :
a, 19 x 64 +76 x 34
b, 35 x 12 + 65 x 13
c, 136 x 68 + 16 x 272
a) 19 x 64 + 76 x 34 = 19 x 64 + 19 x 4 x 34 = 19 x (64 + 4 x 34) = 19 x 200 = 3800
b) 35 x 12 + 65 x 13 = 35 x 12 + 65 x 12 + 65 = 12 x (35 + 65) + 65 = 12 x 100 + 65 = 1265
c) 136 x 68 + 16 x 272 = 136 x 68 + 16 x 2 x 136 = 136 x (68 + 16 x 2) = 136 x 100 = 13600
a) 19 x 64 + 76 x 34 = 19 x 64 + 19 x 4 x 34 = 19 x (64 + 4 x 34) = 19 x 200 = 3800
b) 35 x 12 + 65 x 13 = 35 x 12 + 65 x 12 + 65 = 12 x (35 + 65) + 65 = 12 x 100 + 65 = 1265
c) 136 x 68 + 16 x 272 = 136 x 68 + 16 x 2 x 136 = 136 x (68 + 16 x 2) = 136 x 100 = 13600
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
a, 35 x 34 + 35 x 38 + 65 x 75 + 45 x 65
b, 39 x 8 + 60 x 2 + 21 x 8
c, 58 x 75 + 58 x 50 - 58 + 25
d, 125 x 98 - 125 x 46 - 52 x 25
a.35 x 34 + 35 x 38 + 65 x 75 + 45 x 65
= 35 x (34 + 38) + 65 x 75 + 65 x 45
= 35 x 72 + 65 x (75+45)
= 35 x 72 + 65 x 120
= 35 x 72 + 65 x (72 + 48)
= 35 x 72 + 65 x 72 + 65 x 48
= (35+65) x 72 + 65 x 48
= 100 x 72 + 65 x 48
= 7200 + 3120
= 10320
b.39 x 8 + 60 x 2 + 21 x 8
=39 x 8 + 15 x 4 x 2 +21 x 8
= 39 x 8 + 15 x 8 + 21 x 8
=(39 + 15 + 21) x 8
= 75 x 8
= 600
c.58 x 75 + 58 x 50 - 58 + 25
= 58 x 75 + 58 x 50 - 58 x 1 + 25
= 58 x(75+50-1)+25
= 58 x 124 + 25
= 7192 + 25
= 7217
d.125 x 98 - 125 x 46 - 52 x 25
= 25 x 5 x 98 - 25 x 5 x 46 - 25 x 52
= 25 x 490 - 25 x 230 - 25 x 52
= 25 x (490 - 230 - 52)
= 25 x 208
= 5200
Tính nhanh nếu có thể :
a) 19 x 64 + 76 x 34
b) 35 x 12 + 65 x 13
c) 136 x 68 + 16 x 272
a) 19 . 64 + 76 .34 = 38. 32 + 38 . 68
= 38 . (32 + 68) = 38 .100 = 3800
b) 35 . 12 + 65 . 13 = 35 . 12 + 65 . (12 + 1)
= 35 . 12 + 65 . 12 + 65 = 12 . (35 + 65) + 65
= 1200 + 65 = 1265.
c) 136 . 68 + 16 . 272 = 136 . 68 + 32 .136
= 136 . (66 + 32) = 136 . 100 = 13600
k mik nha!
\(a,19\times64+76\times34.\)
\(=38\times32+38\times68\)
\(=38\times\left(68+32\right)\)
\(=38\times100\)
\(=3800\)
\(b,35\times12+65\times13\)
\(=35\times12+65\times\left(12+1\right)\)
\(=35\times12+65\times12+65\)
\(=12\times\left(35+65\right)+65\)
\(=12\times100+65\)
\(=1265\)
\(c,136\times68+16\times272\)
\(=136\times68+32\times136\)
\(=136\times\left(32+68\right)\)
\(=136\times100\)
\(=13600\)