tính hợp lí.nếu có thể
a.8.17.125
b.35.34+35.36+65.75+65.45
c.4.7^2+16.2^2
d.2^10.13.2^10.65/2^8.104
Tính nhanh : B = 2^10.13 + 2^10.65 / 2^8.104.
B = \(\frac{2^{10}.13+2^{10}.65}{2^8.104}=\frac{2^{10}.\left(13+65\right)}{2^8.104}=\frac{2^{10}.78}{2^8.104}\)
B = \(\frac{2^2.39}{52}=\frac{2^2.39}{2^2.13}\)
B = \(\frac{39}{13}\)
B = 3
B = \(\frac{2^{10}.13-2^{10}.65}{2^8.104}=\frac{2^{10}.\left(13+65\right)}{2^{8.104}}=\frac{2^{10}.78}{2^8.104}=\frac{2^2.39}{52}=\frac{2^2.39}{2^2.13}=\frac{39}{13}=3\)
210.13+210.65/28.104=210.(13+65)/28.104=210.78/210.26=78/26=3
Câu 1: Thực hiện phép tính (tính hợp lí nếu có thể)
a) 35.34+35.86+65.75+65.45
b)7.5^2-32:2^3+9
a, 35.34 + 35.86 + 65.75 + 65.45
= 35.(34 + 86) + 65.(75 + 45)
= 35.120 + 65.120
= 120.(35+65)
= 120.100
= 12000
b, \(7.5^2-32:2^3+9\)
= 7.25 - 32:8 + 9
= 175 - 4 + 9
= 180
Tính giá trị của biểu thức
A,2^10.13+2^10.65/2^8.104
Thực hiện phép tính (Hợp lý nếu có thể) :
a) 35.34 + 35.86 + 65.75 + 65.45
a) 35.34 + 35.86 + 65.75 + 65.45 =
( 35 + 65 ) x ( 34 + 86 ) + ( 75 + 45 )
100 x 120 x 120
100 x 14400
1440000
\(35\cdot34+35\cdot86+65\cdot75+65\cdot45\\ =35\cdot\left(34+86\right)+65\cdot\left(75+45\right)\\ =35\cdot120+65\cdot120\\ =120\cdot\left(35+65\right)\\ =120\cdot100\\ =12000\)
Tính hợp lí:
35.34 + 35.56 + 65.75 + 65.45
= 35.(34+56+75+45)
= 35. 210
= 7350
$35.34 + 35.56 + 65.75 + 65.45$
$=35.(34+56)+65.(75+45)$
$=35.90+65.120$
$=3150+7800$
$=10950$
Tính 2^10.13+2^10.65
2^8.104
\(\frac{2^{10}.13+2^{10}.65}{2^8.104}=\frac{2^{10}.13+2^{10}.5.13}{2^8.2^3.13}=\frac{2^{10}.13\left(1+5\right)}{2^{11}.13}=\frac{2^{10}.13.2.3}{2^{11}.13}=\frac{2^{11}.3.13}{2^{11}.13}=3\)
Bài 2. Tính bằng cách hợp lí nhất:
a) 38. 63 + 37. 38
b) 12.53 + 53. 172– 53. 84
c) 35.34 +35.38 + 65.75 + 65.45
d) 39.8 + 60.2 + 21.8
e) 36.28 + 36.82 + 64.69 + 64.41
Bài 2:
a)38.63+37.38=38(63+37)=3800
b)12.53+53.172– 53.84=53(12+172-84)=5300
c)35.34+35.38+65.75+65.45=35(34+38)+65(75+45)=2520+7800=10320
d)39.8 +60.2 +21.8=8(39+21)+120=480+120=600
e)36.28+36.82+64.69+64.41=36(28+82)+64(69+41)=3960+7040=11000
Bài 2. Tính bằng cách hợp lí nhất:
a) 38. 63 + 37. 38 b) 12.53 + 53. 172– 53. 84
c) 35.34 +35.38 + 65.75 + 65.45 d) 39.8 + 60.2 + 21.8
e) 36.28 + 36.82 + 64.69 + 64.41
a)38.63+37.38
=38.(63+37)
=38.100
=3800
a) \(=38\left(63+37\right)=38.100=3800\)
b) \(=53\left(12+172-84\right)=53.100=5300\)
c) \(=35\left(34+38\right)+65\left(75+45\right)=35.72+65.120=10422\)
d) \(=39.8+15.8+21.8=8\left(39+15+21\right)=8.75=600\)
e) \(=36\left(28+82\right)+64\left(69+41\right)=36.110+64.110=110\left(36+64\right)=110.100=11000\)
2^10.13+2^10.65/2^8.104
( lm đúg mk tick cho nha :P )
\(\frac{2^{10}.13+2^{10}.65}{2^8.104}=\frac{2^{10}.13+2^{10}.13.5}{2^8.2^3.13}\)
\(=\frac{2^{10}.13+2^{10}.13.5}{2^{11}.13}\)
\(=\frac{2^{10}.13\left(1+5\right)}{2^{11}.13}\)
\(=\frac{2^{10}.13.6}{2^{11}.13}\)
\(=\frac{2^{11}.13.3}{2^{11}.13}=3\)
T_i_c_k cho mình nha mơn bạn nhiều ^^