1. (2022一下·黄冈月考) 算一算，填一填

12-3=      13-7+5=      3+9+2=     15-8+3=

12-5=      8+3-5=      12-3-4=     17-5+4=

12-4=      14-7+8=      6+7-4=     16-3-8=

13-7=      13-6=          13-5=        13-5+6=