81.17 - 15.81 phần 81.17+81.4 = ?
( tính nhanh )
a,8/40+-14/35-12/60 b,5/7.5/11+5/7.5/11-5/7.14/11 c,19 5/8: 7/12-15 1/4:7/12
d, 2/5.1/3-2/15:1/5+ 3/5.1/3 e,4/9.19 1/3 - 4/9.39 1/3 g,81.17-15.81/81.17-81.15
a) \(\frac{8}{40}+\frac{-14}{35}-\frac{12}{60}\)
= \(\frac{1}{5}-\frac{2}{5}-\frac{1}{5}\)
= \(\left(\frac{1}{5}-\frac{1}{5}\right)-\frac{2}{5}\)
= \(-\frac{2}{5}\)
b) 5/7.5/11 + 5/7.5/11 - 5/7.14/11
= 5/7.(5/11 + 5/11 - 14/11)
= 5/7.(-4/11)
= -20/77
c) \(19\frac{5}{8}:\frac{7}{12}-15\frac{1}{4}:\frac{7}{12}\)
= \(\left(19\frac{5}{8}-15\frac{1}{4}\right):\frac{7}{12}\)
= \(\frac{35}{8}:\frac{7}{12}\)
= \(\frac{15}{2}\)
d) 2/5.1/3 - 2/15 : 1/5 + 3/5.1/3
= (2/5 + 3/5).1/3 - 2/15 . 5
= 1.1/3 - 2/3
= 1/3 - 2/3
= -1/3
e) \(\frac{4}{9}.19\frac{1}{3}-\frac{4}{9}.39\frac{1}{3}\)
= \(\frac{4}{9}.\left(19\frac{1}{3}-39\frac{1}{3}\right)\)
= \(\frac{4}{9}.\left(-20\right)\)
= \(\frac{-80}{9}\)
g) \(\frac{81.17-15.81}{81.17-81.15}\)
= 1
a)8/40+-14/35-12/60=1/5+(-2/5)-1/5=-2/5
b)5/7.5/11+5/7.5/11-5/7.14/11=5/7.(5/11+5/11-14/11)=5/7.-4/11=-20/77
c)19 5/8:7/12-15 1/4:7/12=(19 5/8-15 1/4):7/12=35/8.12/7=15/2
d)2/5.1/3-2/15:1/5+3/5.1/3=2/15-2/15.5/1+3/15=2/15.2/3+1/5=-5/15=-1/5
e)4/9.19 1/3-4/9.39 1/3=4/9.(19 1/3- 39 1/3)=4/9. 20=80/9
g)81.17-15.81/81.17-81.15=81.(17-15)-15.1.17=81.2-255=162-255=-90
Chúc bạn học giỏi!!! hihi
64.6 + 81.4 + 17.6
64 . 6 + 81 . 4 + 17 . 6
= 384 + 324 + 102
= 708 + 102
= 810
= 64,6+(81,4+17.6)
=64,6+99
=?
\(64.6+81.4+17.6\)
\(=\left(64.6+17.6\right)+81.4\)
\(=6\left(64+17\right)+81.4\)
\(=6.81+81.4\)
\(=81\left(6+4\right)\)
\(=81.10\)
\(=810\)
Học tốt nhé
Tính nhanh:
64.6+81.4+17.6
= 6.(17+64)+81.4
= 6.81+81.4
= 81.(4+6)
= 81.10
= 810
64.6+81.4+17.6
=(64+17).6+81.4
=81.6+81.4
=81.(6+4)
=81.10
=810
64 x 6 + 81 x 4 + 17 x 6
= (64 + 17) x 6 + 81 x 4
= 81 x 6 + 81 x 4
= 81 x (6 + 4)
= 81 x 10
= 810
Tính nhanh:
a)24.156+3.444.8+4.400.6
b)64.6+81.4+17.6
a)=24.156+24.444+24.400
=24(156+444+400)
=24.1000
=24000
b)=64.6+3.27.2.2+17.6
=64.6+54.6+17.6
=6(64+54+17)
=6.135
=810
Tính nhanh:
a)24.156+3.444.8+4.400.6
b)64.6+81.4+17.6
a)24.156+3.444.8+4.400.6
=24*156+24*444+24*400
=24*(156+444+400)
=24*1000
=24 0000
b) 64.6+81.4+17.6
=6*(67+17)+81*4
=6*81+81*4
=81*(6+4)
=81*10
=810
a)24.156+3.444.8+4.400.6
=24.156+24.444+24.400
=24.(156+444+400)
=24.1000=24000
a) 24. 156 + 3.444.8 + 4.400.6
= 24.156 + 24.444 + 24.400
= 24.( 156 + 444 + 400 )
= 24. 1000 = 24000
2 Tính nhanh
a 64 . 6 + 81.4 + 34.3
b 66. 8 +78.2 +24.4
Tính bằng cách hợp lí nhất:
a) 42+37+135+58+63
b) 25.17.8.4.125
c) 43.27+93.43+57.61+59.57
d) 64.6+81.4+17.6
e) 1+11+21+31+...+991
a) \(42+37+135+58+63=\left(42+58\right)+\left(37+63\right)+135=100+100+135=335\)
b) \(25.17.8.4.125=\left(25.4\right).\left(8.125\right).17=100.1000.17=1700000\)
c) \(43.27+93.43+57.61+59.57=43.\left(27+93\right)+57.\left(61+57\right)=43.120+57.120\)
\(=120.\left(43+57\right)=120.100=12000\)
d) \(64.6+81.4+17.6=6.\left(64+17\right)+81.4=6.81+81.4=81.\left(6+4\right)=81.10=810\)
e) \(1+11+21+31+...+991=\left(991+1\right).\left[\left(991-1\right)\div10+1\right]\div2\)
\(=992.\left[990\div10+1\right]\div2=496.\left[99+1\right]=496.100=49600\)
Rút gọn biêu thức
A=3^2.45^4-15^3.9^3/3^3.45^4-5^4.3^10
B=6^30.3^11.7-2^31.5.3^40/2^28.17.3^38-6^27.3^11
C=35.27^8+70.9^11/15.81^6-60.3^20
D=4^6.6^7-9^3.8^6/12^5.2^8+18^3.32^3
Tính hợp lí
1) 2,26,5
2) 4.37.25
3) 25.5.5.27.2
4) 28.64+28.36
5) 43+27+93.43+57.61+59.57
6) 64.6+81.4+17.6
7) (42.43+43.57+43) - 360:4
8) 58.42+32.8+5.16
1=???
2=(4x25)x37=100x37=3700
3=33750
4=28x(64+36)=28x100=2800
5=14386
6=810
7=(43x[42+57+1])-90=4300-90=4210
8=2772
a,4.37.25
=(4.25)+25
=100+25
=125
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