bonjour
X = 1 - ( 2/3 + 1/4 )
X = 1 - ( 8/12 + 3 /12)
X = 12/12 - 11/12 = 1/12 rationnel
Y = ( 3 - 5 /2 ) ( 1 + 1 /5)
Y = ( 6/2 - 5 /2 ) ( 5/5 + 1 /5)
Y = 1/2 * 6 /5
Y = 6/10 = 3/5 décimal
Z = 35/8 x 4/5 = 140/40 = 7 /2
1/12 + 3/5 + 7/2
= 5/60 + 36/60 + 210/60
= 251/60