bonsoir
a) - 5/8 - 7/24 - 1 /6 = - 15/24 - 7/24 - 4/24 = - 26/24 = - 13/12
b ) 4/5 - 2/3 : 10 - 5/6
b = 4/5 - 2/3 x 1/10 - 5/6
b = 4/5 - 2/30 - 5/6
b = 24/30 - 2/30 - 25/30
b = - 3/30
a) 3/8 - ( 7 : 3 - 3:4)
a = 3/8 - (7/3 - 3/4)
a = 3/8 - ( 28/12 - 9/12)
a = 3/8 - 21/12
a = 9/24 - 42/24
a = - 33/24
b = 1/2 - ( - 8/15 + 6/5)
b = 1/2 - ( - 8/15 + 18/15)
b = 1/2 - ( 10/15)
b = 1/2 - 10/15
b = 15/30 - 20/30
b = - 5/30 = - 1/6
3/4 + 9/40 = 30/40 + 9/40 = 39/40
1/40 représente les eaux douces