ex 5
7/4 + 1/2
il faut mettre les fractions sous un même dénominateur
7/4 + 1x2/2x2 = 7/4 + 2/4 = 9/4 = 2x3/2x2 = 3/2
11/3 - 2/3 = (11-2) / 3 = 9/3 = 3
5/6 + 1/2 = 5/6 + 1x3/2x3 = 5/6 + 3/6 = (5+3) / 6 = 8/6 = 2x4/2x3 = 4/3
-1/4 + 1 = -1/4 + 4/4 = ... tu finis
et
2 - 4/3 = 6/3 - 4/3 = .. tu finis
même raisonnement pour colonne de droite
7/4 - 1/4 = (7-1) / 4 = ...
1 + 1/3 = 3/3 + 1/3 = ...
1/2 + 1/3 = 3/6 + 2/6 = ...
1/5 + 3/10 = 2/10 + 3/10 = ...
5/8 + 11/8 = (5+11)/8 = ..
