Fraction mathématique n 45 merci d avance

1)  1/14 + 5/21 = 3/42 + 10/42 = 13/42
2)  8/55 + 7/44 = 32/220 + 35/220 = 67/220
3)  5/36 + 11/9 = 5/36 + 44/36 = 49/36
4)  2/3 + 3/4 = 8/12 + 9/12 = 17/12
5)  9/8 + 5/12 = 27/24 + 10/24 = 37/24
6)  5/12 + 3/10 = 25/60 + 18/60 = 43/60