(4sur5+3sur5)×1sur2? 4sur5 +3sur5×1sur2? 17sur8-3sur4×5sur3? (17sur8-3sur4)×5sur3?,

1) 7/5 x 1/2
  = 7/10 = 0,7

2) 4/5 + 3/10
  = 4x2 / 5x2   +   3/10
 = 8/10 + 3/10
 = 11/10 = 1,1

3) 17/8 - 15/12
    = 17x3 / 8x3     -     15x2 / 12x2
    = 51/24 - 30/24
    =  21/24 = 7/8 = 0,875

4) [(17x2 / 8x2) - (3x4 / 4x4)] x 5/3
 = (34/16 - 12/16) x 5/3
 = 22/16 x 5/3
 = 110/48 = 55/24