`#PhuonggYaa.`

a. 16 569 330

    24 425 739

b. 14 711 334

    24 935 708

c. 23 222 460

   28 495 512

d. 12 585 992

    13 837 260

a.4674 x 3545

   4563 x 5353

  b.4521 x 3254 = 14711334

 .4387 x 5684 = 24958869

   c.4436 x 5235 = 23222460

   5242 x 5436 = 28495512

d.3646 x 3452 = 12585992

  3252 x 4255 = 13837260

Học tốt

57 x 76 + 13 x 57 + 11 x 57

= 57 x ( 76 + 11 + 13 )

= 57 x 100

= 5700

57 x 76 + 13 x 57 + 11 x 57

=  57 ( 76 + 13 + 11 )

= 57 x 100

= 5700

Ez bạn ơi

471/709 x 49/57 + 479/709 x 8/57

= 471/709 x (49/57 + 8/57)

=471/709 x 1

Chúc bạn học tốt ! Nếu thấy mình lm đúng thì k cho mình nha :)

a,24.57+43.24

=24.(57+43)

=24.100

=2400

b,12.19+12

=12.(19+1)

=12.20

=12.10.2

=120.2

=240

c,43.27+93.43+57.61+59.57

=43.(27+93)+57.(61+59)

=43.120+57.120

=120.(43+57)

=120.100

=12000

d,64.6+81.4+17.6

=64.6+27.3.2.2+17.6

=64.6+54.6+17.6

=(64+54+17).6

=135.6

=810

a) 24 . 57 + 43 . 24

= 24 . (57 + 43)

= 24 . 100

= 2400

b) 12 . 19 + 12

= 12 . (19 + 1)

= 12 . 20

=240

c) 43 . 27 + 93 . 43 + 57 . 61 +59 . 57

= 43 . ( 27 + 93) + 57 . (61 + 59)

= 43 . 120 + 57 . 120

= 120 . (43 + 57)

= 120 . 100

= 12000

57/12 = 114/24

57/13= 114/26

Mà 114/x như trên nên x=25

Cảm ơn bạn !

\(\frac{471}{709}\cdot\frac{49}{57}+\frac{471}{709}\cdot\frac{8}{57}\)

\(=\frac{471}{709}\left(\frac{49}{57}+\frac{8}{57}\right)\)

\(=\frac{471}{709}\cdot1=\frac{471}{709}\)

=1/1-1/2+1/2 -1/3+1/3-1/4....... 1/56 -1/57+1/57-1/58

=  1/1-1/58

= 57/58

\(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+...+\frac{1}{56.57}+\frac{1}{57.58}\)

\(=\frac{1}{1}-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{56}-\frac{1}{57}+\frac{1}{57}-\frac{1}{58}\)

\(=\frac{1}{1}-\frac{1}{58}\)

\(=\frac{57}{58}\)