Calculs simples, additions et soustractions, calcule le plus rapidement possible

12 - 7 + 8	=			13 + 6 + 9	=
15 - 2 + 7	=			18 - 15 + 3	=
14 + 14 + 14	=			16 + 6 - 8	=
10 - 4 + 11	=			19 + 7 - 2	=
24 - 12 + 4	=			28 - 9 - 4	=