问题 计算题
我会填。
34+8=42,42-7=35。→  34+8-7
                                      =42-7
                                      =35
(1)47-12=35,35-30=5(2)15-7=8,8+23=31(3)17+7=24,24+16=40
答案

(1)47-12-30

         =35-30

         =5  (2)15-7+23

         =8+23

         =31(3)17+7+16

          =34+16

          =40

单项选择题
单项选择题