bonjour

D = 1 - 5/4 : 2/5

 =  1 - 5/4 x 5 /2

  = 1 - 25/8

  = 8/8 - 25/8

  = - 17/8

E =  6 - 4 ( 1/4 - 1 )²

  = 6 - 4 ( 1/4 - 4/4 )²

  = 6 - 4 ( - 3 /4 ) ²

  = 6 - 4 * 9/16

  = 6 - 36/16

  =  96/16 - 36/16

  = 60 /16  =  15/4

F =  2/3 - 1/4 x 6 + 7

  = 2/3  - 6/4 + 7

  =  8/12 - 18/12 + 84/12

  = 74/12  = 37/6

G = ( 8/7 - 2 ) : 9/14

   = ( 8/7 - 14/7 ) x 14/9

   = - 6 /7 x 14 /9

   = -  84/63

   = - 4 / 3

H est la même chose que G

I = 15 /5 = 3

J =   8 - 16/3 - 4/3 + 8/9

  =  8 -  20/3 + 8/9

  = 72/9 - 60/9 + 8/9

  = 20/9