a) \(\dfrac{25}{37}\times\dfrac{18}{29}+\dfrac{18}{29}\times\dfrac{12}{37}\)

\(=\dfrac{18}{29}\times\left(\dfrac{25}{37}+\dfrac{12}{37}\right)\)

\(=\dfrac{18}{29}\times\dfrac{37}{37}\)

\(=\dfrac{18}{29}\times1\)

\(=\dfrac{18}{29}\)

b) \(\dfrac{31}{85}\times\dfrac{11}{19}+\dfrac{31}{85}\times\dfrac{12}{19}-\dfrac{42}{19}\times\dfrac{31}{85}\)

\(=\dfrac{31}{85}\times\left(\dfrac{11}{19}+\dfrac{12}{19}-\dfrac{42}{19}\right)\)

\(=\dfrac{31}{85}\times\dfrac{-19}{19}\)

\(=\dfrac{31}{85}\times-1\)

\(=-\dfrac{31}{85}\)

c) \(\dfrac{16}{53}:\dfrac{17}{9}-\dfrac{16}{53}:\dfrac{17}{8}\)

\(=\dfrac{16}{53}:\left(\dfrac{9}{17}-\dfrac{8}{17}\right)\)

\(=\dfrac{16}{53}:\dfrac{1}{17}\)

\(=\dfrac{16}{901}\)

c) \(\dfrac{1}{5}\times\dfrac{12}{31}\times\dfrac{4}{3}+\dfrac{19}{31}\times\dfrac{4}{15}\)

\(=\dfrac{4}{15}\times\dfrac{12}{31}+\dfrac{19}{31}\times\dfrac{4}{15}\)

\(=\dfrac{4}{15}\times\left(\dfrac{12}{31}+\dfrac{19}{31}\right)\)

\(=\dfrac{4}{15}\times\dfrac{31}{31}\)

\(=\dfrac{4}{15}\times1\)

\(=\dfrac{4}{15}\)

a: =18/29*(25/37+12/37)

=18/29

b: =31/85(11/19+12/19-42/19)

=-31/85

c; =16/53(9/17+8/17)=16/53

d: =4/15(12/31+19/31)=4/15

43x (85-81) + 85x(81-43)

= 43 x 85 - 43 x 81 + 85 x 81 - 85x 43

= 43 x 85 - 85 x 43 + 85x 81 - 43x 81

= 0 + 81 x ( 85 - 43 ) 

= 0 + 3402

= 3402

43x(85-81)+85x(81-43)=43x85-43x81+85x81-85x43

=(43x85-85x43)+(85x81-43x81)

=0+81x(85-43)

=81x42

=3402

43 x (85 - 81) + 85 x (81 - 43)

= 43 x 85 - 43 x 81 + 85 x 81 - 85 x  43

= 43 x 85 - 85 x 43 + 85 x 81 - 43 x 81

= 0 + 81 x (85 - 43) 

= 0 + 3402

= 3402

Nhớ  nha!

2014 x (128 x 68 - 64 x 136) + 2015

2014 x (8704 - 8704) + 2015

2014 x 0 + 2015

0 + 2015

= 2015

A = 2015

a )   x :   − 7   –  6  =   − 15  x :   − 7   =   − 9 x  =   − 9 . − 7   x  =  63

b ) x :  12  –  12  =   − 37 x :  12  =   − 25 x  =   − 25 . 12 x  = 3 00

c ) x :   − 25   +  81  =  85 x :   − 25   =  4 x  =  4 . − 25 x  = − 1 00

x :   − 25   +  81  =  85          x :   − 25   =  4                     x  =  4 . − 25                     x  = − 1 00

Bài 1: 

a, 0

b, 0

c, 6

d, 1

e, 5

Bài 1 :

a , 0

b,0

c,6

d,1

e,5

Bài 2:

a ,

bài 3 :

a sai vì 6 x 6 - 1 =5 rồi 

b, sai vì 2 số giống nhau k thể nhân dc 1 số có tận cùng là 7 

a)=0

b)=0

c)=6

d)=1

e)=5

tính thường hay tính nhanh vậy bạn?

Nguyễn Hoàng Thiên Di

tính thường cx đc mà tính nhanh càng tốt nha

đợi mik xíu vì giải hơi dài ạ

a: \(32684+41325+316+675\)

\(=\left(32684+316\right)+\left(41325+675\right)\)

\(=33000+42000=75000\)

b: \(25\cdot18\cdot4\cdot2\)

\(=18\cdot2\cdot\left(25\cdot4\right)\)

\(=36\cdot100=3600\)

c: \(19\cdot81+19+18\cdot19\)

\(=19\left(81+1+18\right)\)

\(=19\cdot100=1900\)

^{A, 32684 + 41325 + 316 + 675}

^{=(32684+316)+(41325+675)}

=33000+42000

=75000

^{B, 25 x 18 x 4 x 2}

^{=(25x4)x(18x2)}

^=100x36

⁼³⁶⁰⁰

^{C, 19 x 81 + 19 + 18 x 19}

=19x(81+18+1)

=19x100

=1900

C bị sai đề bạn ơi