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

= 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

= 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

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

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

a,810

b,780

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) \(1+11+21+31+...+991=\left(991+1\right).\left[\left(991-1\right)\div10+1\right]\div2\)

\(=992.\left[990\div10+1\right]\div2=496.\left[99+1\right]=496.100=49600\)

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

đó tui giải câu a thu

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