Bonjour
a. 11/10 + 3/2 = 11/10 + (3 x 5) / (2x 5) = 11/10 + 15/10 = 26/10 = (2 x 13) / (2 x 5) = 13/5
11/10 + 3/2 = 1,1 + 1,5 = 2,6
b. 9/2 - 7/5 = (9 x 5) / (2 x 5) - (7 x 2) / (5 x 2) = 45/10 - 14/10 = 31/10
4,5 - 1,4 = 3,1
c. 1/4 + 3/2 - 14/20 = (1 x 5) / (4 x 5) + (3 x 10) / (2 x 10) - 14/20 = 5/20 + 30/20 - 14/20 = 21/20
1/4 + 3/2 - 14/20 = 0,25 + 1,5 - 0,7= 1,05.