小学一年级30以内加减混合3连加减口算题

20 - 13 + 9 =26 + 4 - 13 =22 - 14 + 15 =14 + 7 - 13 =22 + 7 + 1 =17 + 9 + 4 =8 - 5 + 18 =14 + 8 - 4