Bonjour,
5/(-12) = -5/12
-1/3 = (-1 × 4)/(3 × 4). = -4/12
on a -5/12 < -4/12 soit 5/(-12 )< -1/3
4/3 = (4 × 4)/(4 × 3) = 16/12
(-5)/(-4) = 5/4 = (5 × 3)/(4 × 3) = 15/12
on a 15/12 < 16/12 donc (-5)/(-4) < 4/3
19/20 = (19 × 8)/(20 × 8) = 152/160
31/32 = (31 × 5)/(32 × 5) = 155 /160
on a 152/160 < 155/160 donc 19/20 < 31/32