四、退位減、退位滿五減基本練習(xí):
18-9 17-9 16-9 15-9 14-9 13-9 12-9 11-9 10-9
17-8 16-8 15-8 14-8 13-8 12-8 11-8 10-8
16-7 15-7 14-7 13-7 12-7 11-7 10-7
15-6 14-6 13-6 12-6 11-6 10-6
14-5 13-5 12-5 11-5 10-5
13-4 12-4 11-4 10-4
12-3 11-3 10-3
11-2 10-2
10-1
18-9 17-9 16-9 15-9 14-9 13-9 12-9 11-9 10-9
17-8 16-8 15-8 14-8 13-8 12-8 11-8 10-8
16-7 15-7 14-7 13-7 12-7 11-7 10-7
15-6 14-6 13-6 12-6 11-6 10-6
14-5 13-5 12-5 11-5 10-5
13-4 12-4 11-4 10-4
12-3 11-3 10-3
11-2 10-2
10-1