Sagot :

Bonjour,

A: 1+1/4 = 5/4

B: -2/4 = - 1/2

C: 1+3/4 = 7/4

AB: 5/4 + 2/4 = 7/4

BC:  2/4 + 7/4 = 9/4

CA: 7/4 - 5/4 = 2/4 = 1/2