1、11-9 18-9 11-8 11-7 11-6 11-5 11-4 11-3 11-2 12-9 12-8 12-7 12-6 12-5 12-4 12-3 13-9 13-8 13-7 13-6 13-5 13-4 14-9 14-8 14-7 14-6 14-5 15-9 15-8 15-7 15-6 16-9 16-8 16-7 17-9 17-8 11-9 11-8 11-7 11-6 11-5 11-4 11-3 11-2 12-9 12-8 12-7 12-6 12-5 12-4 12-3 11 11 11 11 11 11 11 11 9 8 7 6 5 4 3 2 =2 =3
2、 =4 =5 =6 =7 =8 =9 11-9 11-8 11-7 11-6 11-5 11-4 11-3 11-2 12-9 12-8 12-7 12-6 12-5 12-4 12-3 11 11 11 11 11 11 11 11 9 8 7 6 5 4 3 2 13-9 13-8 13-7 13-6 13-5 13-4 14-9 14-8 14-7 14-6 14-5 15-9 15-8 15-7 15-6 16-9 16-8 16-7 17-9 17-8 18-9 12 12 12 12 12 12 12 13 13 13 13 13 13 14 14 14 14 14 15 15 1
3、5 15 17 18 20以内退位减法表 9 8 7 6 5 4 3 9 8 7 6 5 4 9 8 7 6 5 9 8 7 6 9 8 7 9 8 9 竖着看 11-9 11-8 11-7 11-6 11-5 11-4 11-3 11-2 12-9 12-8 12-7 12-6 12-5 12-4 12-3 13-9 13-8 13-7 13-6 13-5 13-4 14-9 14-8 14-7 14-6 14-5 15-9 15-8 15-7 15-6 16-9 16-8 16-7 17-9 17-8 18-9 20以内退位减法表 横着看 11 12 13 14 15 16 17 18 9
4、 9 9 9 9 9 9 9 11 12 13 14 15 16 17 8 8 8 8 8 8 8 7 7 7 7 7 7 6 6 6 6 6 11 12 13 14 15 16 11 12 13 14 15 11 12 13 14 11 12 13 11 12 11 5 5 5 5 4 4 4 3 3 2 11-9 11-8 11-7 11-6 11-5 11-4 11-3 11-2 12-9 12-8 12-7 12-6 12-5 12-4 12-3 13-9 13-8 13-7 13-6 13-5 13-4 14-9 14-8 14-7 14-6 14-5 15-9 15-8 15-7
5、15-6 16-9 16-8 16-7 17-9 17-8 18-9 20以内退位减法表 斜着看 18 17 16 15 14 13 12 11 9 8 7 6 5 4 3 2 17 16 15 14 13 12 11 9 8 7 6 5 4 3 16 15 14 13 12 11 9 8 7 6 5 4 15 14 13 12 11 9 8 7 6 5 11-9 11-8 11-7 11-6 11-5 11-4 11-3 11-2 12-9 12-8 12-7 12-6 12-5 12-4 12-3 13-9 13-8 13-7 13-6 13-5 13-4 14-9 14-8 14-7 1
6、4-6 14-5 15-9 15-8 15-7 15-6 16-9 16-8 16-7 17-9 17-8 18-9 20以内退位减法表 12-8 13-8 14-8 15-8 16-8 12-7 15-7 12-6 15-6 12-5 13-5 13-7 14-7 13-6 14-6 摘果子摘果子 12 12 - - 3 = 93 = 9 13 13 - - 8 = 58 = 5 13 13 - - 6 = 76 = 7 11 11 - - 8 = 38 = 3 15 15 - - 7 = 87 = 8 113 8 135 157 124 146 168 179 2 3 4 5 6 7 口算比赛 作业： 观察第23页的20以内退位减法 表，和我们整理的有什么不同？请 你找出排列的规律。
