20以内三连加减混合口算练习题(72).docx

《20以内三连加减混合口算练习题(72).docx》由会员分享，可在线阅读，更多相关《20以内三连加减混合口算练习题(72).docx（56页珍藏版）》请在淘文阁 - 分享文档赚钱的网站上搜索。

1、2 + 13 + 5=6+5+9=17-1 + 2 =17-9-6=8 + 14-11 =17-4 + 1 =4 + 17-11=5+6-3二8 -5 + 9=7-5+6=17-10 + 13 =10-2-6=4+5+8=2 + 10-4=7 + 16-12 =16-12 + 16=5-5 + 16=1 + 15-8=16-5 + 5 =6 + 12-4=6 + 7-11=20 - 15 + 6=20 + 1-5=19-7 + 2 =11 + 5-7=19-11-7=1+3+6=15 + 16-14=17 + 14-20=6+4+8=15 - 12 + 13 =14 + 11-6=7-5+7=

2、4+1-1=11 - 10 + 17=14 + 11-9=8 + 12-3 =17-6 + 3 =11-9 + 9=8+1+8=3-2 + 12二11 + 4-6=7 + 17-6=2 + 7 + 10=12 + 4-11=18 + 17-18=10-9 + 5 =7 + 12 - 13 =3+8-2二3-2 + 17=4 + 10 + 3 =19-7-4=18-6 + 6=16-7 + 8=12 - 10 + 3 =19-11 + 5 =11 + 1 + 5=13-2-1=1 + 19-14=3+7+8=19 + 9-9=6 + 17-4=7+1+5=17-17 + 17=15 + 12 -

3、 8=4+5+2=14-13 + 11=8-7 + 12 =20 + 3 - 10=11-6 + 5 =14-14 + 8=7-4+9=15 + 20-19=3-2 + 16=13-8 + 1=3 + 12 + 4=12-9 + 4=6-3+5=3-2+7二3+7+4=5+1+4=13 + 12-6=6 + 18-18=13 + 15-8=16-13 + 15 =18-4 + 2 =1 + 18-13 =20 + 6-12 =20-4-3 =8-5 + 16=13-9 + 4 二5-5 + 10=10 + 20-12=18 + 11-12=16 - 14 + 11=18 - 1 - 17=4+

4、3+5=10 + 6-3 =20-4-4=3+6-2=11 + 17-10=1 + 5 + 14=8 + 14-20二15 + 16-17=9-2+5二1+4-3二12 + 14 - 6二11 - 11 + 13 =14-2-12 =19-12 + 3 =2+4+9=15 - 14 + 12 =15 - 15 + 15 =10-9 + 8=12-3-8=7-7+6=17 + 12 - 19=8 + 7-15=3+1+7=10-8 + 3 =16 - 12 - 1=7 + 20-15=6 + 8-12 二6-4 + 18=20-11 + 6=8+7+3=4 + 10 + 5=20 - 12 -

5、4=12-4 + 6=3 + 6 + 10=5+6-7二11-1-1=12 + 4-5 =16 -4 + 8二16-2-6=16-4 + 3 =19 -11 + 6=20-16-3 =13 + 13-7=11 + 8-1 =7-7+3二11-8 + 9=3+3+8=19 -11 + 1=13 + 4-2二17 + 1-9=5 + 16-16=12-1-4=1 + 14 + 4=20-9 - 10=18-15 + 7=3+8+3=13-2-2 =16 + 18-15=14-11 + 2 =20-6-3 =13-4-8=6 + 15 - 6 二16-13 + 16=9-3+5=17-5 + 5 =

6、5 + 17-3 =5+8-8=11 + 4-7=10-10 + 8=14-5-4=16-11-2=12 + 13 - 14=15-6 + 10=8-2 + 10=4 + 16-3二14-14 + 17=6 + 15 - 15=11 - 11 + 9=20 + 2 - 18=12-2- 10=7-7 + 16=6+5+7=15 -3 + 3 =18-18 + 1=16 + 20-18=8 + 10 + 2 = 7+5+6=2 + 18-4=6+9+3=16-8-1 = 9-4+9=11-7-2 =18 - 18 + 3 =15 - 10 + 15 =9 + 15-16= 14-2-9=6-3

7、+ 17=8+5+3=15-7-4=10-9 + 11=1 + 2 - 3二4+8+5=15 - 10 + 12 =17-5-4=10 + 17-7=12-4-8=20-5-2 =18-17 + 12=13 -10 + 6=5+4+3=9 + 16-19=14-13 + 19=5 + 17-15 =15 + 7-12 =17 + 2-7=19-8-7=15-5-5 =19 + 10-9=1 + 13-3 =5-2+8=2+9+5=15 - 5 + 5 =17 + 9-9=10 + 9-14=4 + 15 - 12 =10 + 7-8=11-8 + 1=15 - 5 + 7二18-1 + 3 =

8、8-5 + 15二11-4 + 12 =17-13 + 7=4 + 17-9=6-1+7=15 - 1 - 14=3+3+4=4-3+5=8+3+2=10-10 + 14=8 + 12-9=5+2+6=11 -1 + 2 =16-6 + 10=10-10 + 11 =18 - 16 + 13 =1 + 8 + 11=10-6 + 15 =20-3-13 =17-6 + 1=20 - 6 + 2二8-8 + 11=12-3-3 =5 + 12-2 =18-4 + 6=18 - 17 - 1=11 + 4-15 =19-2- 10=20-2 + 2 =15 + 8-20=10 + 7 + 1=9-

9、8+4二6 + 20-13 =2 + 16-10=13-6 + 10=9+7+1=9-5-4=4 + 7-10=11 + 12-6=18-3- 12 =12-5 + 7=16 + 2-4=12 + 5 + 2 =5 + 20-18=17-3-3 =6 + 6-12 =16 + 2-1=16 + 15-19=1+6+7=9-2-2=17 + 5 - 13 =9+8-3二15 + 4-18=12-3-2 =13 - 10 + 14=5-4 + 10=10 + 9-10=19-6 + 7=11 + 7-1 =17 + 12-11 =12 + 3 + 4=2-2+4=9 + 13-9二9+9-7二19

10、 - 14 + 12 =7-5 + 17=10 + 2 + 6=4-4 + 19 二18 + 3 - 16=16 + 9-14=13 + 5 - 18=20-20 + 11=19 + 1-20=19 + 19-19=18 + 17-16=19-6-9=12 - 10 + 14=6+3-8二7+6+3=19-6-2 =15-10-3 =17 - 12 + 11=13 + 3 + 3=5 + 19-5 = 18-6-2 = 20-5-6=6 + 16-7= 9+4+3=16-3-9=19-6-11=1 + 12 + 2 =4 + 19-16=5 + 13-5 = 9-1-2=16 -13 +14=

11、3 + 4 + 11=6 + 15-19 =1 + 10 + 6=10-6 + 8=18-5 + 3 =20-19 + 13 =11-1-2 =17 - 12 + 4=18-16 + 11 =17-6-7=10-2-5 =1 + 1 + 17=2 + 12-7=18 + 9-20=10-4-1 =6-4-2=16-2 + 4=12-9 + 11 =12 - 11 + 3 =7-7 + 15 =12-1 + 1=9-4+5=15 + 3-10=2+3+7=13 + 5-13 =20-19 + 5 =13 -4 + 5=14-13 + 2 =10 + 15 - 19=16 + 6-2 =20-5-

12、 13 =1+9+9=4 + 12 - 13 =9+2+8=13 + 18-12 =17-5-1=6 + 13 - 14=11 - 11 + 3=7 + 15 - 17=13-8-1=17 + 7-20=7 + 19-18=6 + 19-11=19-4-13 =13 + 14-20=7-4 + 16=8 + 13 - 11=4 + 11 - 1=6-2+3二12 +5 + 3=4 + 14-13 =11-9 + 5=4-3 + 14=5 + 18-19=10-4-2 =17-5 + 1=12 + 17-17=16 - 15 - 1=3+9+3=15 -13 + 12=12 + 6-9=7+1+

13、3=10-7 + 2 =11 -1 + 3 =9 + 19-13 =15 + 13 - 12 =6+9+1=3+1+4=8-5-2=20 - 12 - 8=1+5-2=5+6+8=11 + 17-9=2 + 11 + 1 =10 + 19-15 =3+2+4=1 + 10 + 8=I + 17-5 =12-2-3 =18-10 + 10=15-2 + 5 =18 + 17-15 =8-6+2=14-8 + 12=1-1 + 19=7+3-6二II + 7-2 =3+4+6=1+4+8=5 + 4- 5二9 + 8-16=7-2+8二11-10-1=5-4 + 16=12 -12 + 7= 10

14、-4-6=14-4-5 =6 + 14-15 =6+7+3=18-10-2 =15-2-6=18 - 15 + 6=6-5 + 14=17 - 16 + 12 =16-12 + 11 =20 - 18 + 17=5+2+4=13 - 11 + 3 =5 + 18-9=11 -11 + 6=1 + 14-14=9+6+2=14-12 + 8=16 + 14-14=14-1-9=9 + 15 - 17=2+1+4=10-9 + 18=1 + 4 + 15 =7 + 10 + 2 =14 + 7-11 =9-1+9=4+4+4=3-3 + 16=16 + 6-11 =17-12 + 10=17 +

15、8-15 =11-1-9=15-5 + 6=20-12 + 9=12 + 8-4=14-11 + 12=20-4-7=4+6-2二20 + 2-9=19 + 9-12 =10 + 6 + 3 =20-19 + 3 =15 + 5 - 19=11 + 8 - 10=15 -10 + 7=4 + 2 + 14=11-8 + 3 =18-7-9=14-11 + 9=8+4-3二15 + 14-20=4+8+8=5-2+6二11 + 17-18=2+7-9二14-3-7=19 -11 + 7=18 + 1-5 =1 + 13-6=18-7-5 =2 + 17-6=6+1+3=5+7+1=16-9-6=

16、11 + 17-16=2+6+5=19-6-6=5 + 12-5=11-5 + 10=10 + 13-9=11-2-4=5 + 10-4=19 + 15 - 19=7+4+6=13 + 15 - 13 =19-3-6=20 + 9-14=13-5 + 1 =8 + 11 - 18=20-15 + 8=20-19 + 8=19 -6 + 5 =9 + 2 + 4=20-7 + 4二8-7 + 15二4 + 5 + 10=12 + 20 - 20=4+1+7=8 + 12-5 =20 - 5 - 15=9 + 20-19=7 -4 + 6二6-5+7二5-5+6=17-2-5 =7-2 + 5 二

17、16 + 7-13 =19 + 8-16=11 + 12-7=5 + 10 + 3 =13 -5 + 12 =19-7-7=1+7-3=13 + 1 - 10=16 - 14 + 15 =20-3 + 2=17 - 13 + 3 =12 + 12 - 10=6 + 2 + 12 =8 -4 + 7二6 + 9-10=9 + 13-3 =9-6 + 2二6 + 15-2 =4 + 18-16=5-4-1=14 + 18-20=12-9 + 7=20-17 + 14=4-4 + 3二14-13 + 17=20 -17 + 3 =7 + 5 + 5=19 - 14 + 2 =20 + 4-16=7

18、+ 14-8=19 + 2 - 10=19 + 5 - 12 =8 + 14-8=10 + 14-20= 14-3-9=3 + 10 + 6= 14-6 + 5 =5-5+5=6+6-4=20-15-4=20 - 20 + 8=19-14 + 15 =13 + 2 - 11 = 8+4+1=18 - 1 - 13 = 2+4-1=6-1+8=19 + 1 - 13 =15 + 10-17= 3 + 18-6=14 + 13 - 14=4 + 14 + 1=8 + 18-14=18 -17 + 3 =12 + 2-7=15-4-8=1+8+1=13-5-4=20-15-3 =14-14 + 9=

19、20 + 10-13 =19 - 19 + 4=3+7+9=14-11 + 5 =12 + 19-13 =15 + 10-6=17-8-3 =1+1+5=7 + 18-5=9 + 11 - 14= 2+5+6=6-2+7二8+3+6=3 -3 + 15=13 - 12 + 14=5 - 5 + 9=19 + 5-5=8 + 11-7=17 -10 + 8= 17-2- 14=13 -12 + 3 =10-8 + 17= 11-2-7=8-7 + 16=15 -4 + 7=2+2+3=5-5+4=8 + 13-13 =17-14 + 14=20 + 19-19=8-7 + 10=7-3 + 11

20、=8 + 19-18=17-14 + 11= 12-4 + 12 =16 + 3 - 15=20-7-9=2 + 15 + 1=9-5-1=2+3+3=18-5-6=8-8 + 16=20-8 + 7=10-4-3 =3 + 2 + 11=10 + 4-6=20-7 + 1=9-9 + 17=11 + 14-18=11-9 + 7=10-8 + 10=20 + 4-12=20 - 10 - 3二7-3+7=13 + 2 + 3=6+6-9二8 + 10-13 =20-5-10=12 + 1 - 11=8+3-8二7+1-4=3 + 14- 5二20 - 16 - 1=17 + 5 - 15 =

21、8 + 18-16=9-4-4=7 + 16-7=18-14 + 12=5-1+7=10-3 + 13 =5 -4 + 2二6+2-7二16 + 13 - 16=13 - 1 - 10=11-2-8=14 + 3 - 12 =10-9 + 16=12-7 + 15 =17-2-4=20-8 + 2 二17-1-3 =8-2+2=1+6-7=7-3+6=11 + 11-16=10 + 1 + 9=13-3-3 =6-6+5=9-9 + 10=12 + 12-4=20-8 + 6二16-7 + 5 =12 + 19-14=4+2+3=19 + 9-13 =12 + 19-17=19 + 20-19

22、=17-11 + 12 =16-9 + 12 =16-3-13 =17 + 8-13 =20 - 16 + 4二3+6+3=17 + 4-1=1-1+6=19-19 + 14=4 + 14-10=3 + 12 - 12 =6+3+2=1 + 12 + 5 =20-15 + 3 =16-8 + 4=5-1+5=13 + 15 -19=10-6 + 16=15-11-2=8 + 10-8=2 + 11 - 13 =7 + 11-18=13 + 18-16=18-8 + 6=4+3+7=12 + 12 - 18 二17 + 16-13 =4 + 14-11=18 -14 + 8=10-4 + 4=7

23、-6+4二2+7-5=2+8+1=19-9-1=1 + 11 + 3 =12 + 4-4 二17 - 11 + 14=20-4 + 2二20 - 12 - 1=17-8 + 2 =15 - 14 + 4=6+9-9二15 + 12 - 13 =18 - 11 + 11 =1 + 2 + 16=9-6+6=9-8+2=1 + 13 - 10二19 - 15 + 5 =2+8-3=20-17 + 8=13-2-3 =19-10 + 4=12-3-5=13-7 + 12 =18 - 17 + 8=5 + 16-14=7 + 14-2 =14-4-7=19-11 + 12=16 + 15 - 13=8

24、-4+5=17 - 17 + 16=16 + 5 - 19=11 + 12 - 10=5+8+4=12-7 + 4二8-6+7=3 + 13-5 =17 + 5 - 19=14-2 + 2 =10-9-1=18 - 15 -1 =7+6+5=18 - 13 - 1=10 + 5 - 14=19-8 + 6=14 + 3-1 =9-6+9=7+4-8二10 + 3-8=3+4+1=19 + 9-14=4 + 14-17=18 + 4-5 =6 + 14-7=20 -19 + 2 =13-9-1=19 + 4-14=17 + 10-11=10 + 1 + 3 =20-3-7=9 + 5-10=16

25、-9-2二9-7 + 16=17-4-7=20-18 + 18=4+2+8=17-6 + 4=14-5 + 10=5 + 14-7=8 + 19-16=19 + 2 - 14=20 + 10-19=2+6+3=1 + 20-18=12-3 + 6=20-1-6=12 + 3 - 14=2-1 + 12 =6-4 + 14=20-5-9=17 -10 + 3 =12-4-2 =13 - 12 + 15 =8-3+9二10 + 6-15 = 6-1+5=15 - 13 + 9=6 + 16-5=16-1-13 = 13-5-7=2+8-4=8-4 + 14=11-7-4=9-9+6=3 + 2 +

26、 14=14 + 9 - 11=12 + 12-9=4 + 15 - 17=1+3+7=13 + 13 - 11=12 + 3-8=11 + 6-4=7 + 19-6=4-2+7=15 + 6-5二3 + 14-15 =12 - 10 + 12=15 + 4-1=19 + 10-10=11 + 12 - 11=18-16 + 15=18-8 + 7=17-9 + 1二1+3+1=17 - 13 - 3 =9 + 19-16=18 + 5-13 =6+3-7二11-3 + 1=12-1-8=16-10 + 12=18 + 2-2 =14-11 + 14=15 - 15 + 4=5+9+4=14-

27、11 + 13 =6+4+6=3 -3 + 4=17 + 3-5=10 + 15-7=9-3-1=19-11-8=1 + 16-6=15-5-7=6-6+9二9 + 14-12 =12 + 10-12 =16-10 + 11 =20-6 + 3=14 + 8-11=9 + 13 - 13 =12-4 + 8=5+5-9二15 + 1 - 16=13-3-10=15-7-6=15-4-4=19-8 + 3二13 + 9-19=1 + 3 + 13 =5 + 15-8=18-3-15 =19 - 17 + 14=4+2+9=2 + 1 + 16=7 + 10-6=14 + 8-16=15 + 10

28、-13=2+6+7=6 + 15 - 16=17-10 + 11=3 -1 + 11=1-1 + 16=2 + 4 + 10=20-16 + 6=16-9-1=15-7-7=13-8 + 8二18-6-11 =2 + 14 + 2 =8-4-3=10-9 + 3 =8-5-1=12 -12 + 9=6-6 + 15二2+3+5=5 + 13 + 2=15-8 + 6二13 -4 + 1 二8+3-2=5 + 10-2 =12-1 + 9=11 + 11-12 =10 + 9-12 =7-6+6=15 -1 + 2 =20-5 + 5 =9 + 10 + 1=11 + 10-20=1 + 14

29、+ 3 =20-3 + 1=13 + 2-1=5 + 3 + 11=20 + 9 - 11=20 -19 + 1=8-1-4=20 + 3-9=9 + 20-17=14-4-4=20-1- 16=14 + 5-7=1 + 5 + 10=6+9-6=12 - 10 + 17=9 + 16-8=17 + 19-17=12-3 + 5 =3-1-1=8+8-3二2+5+8=16-9 + 6二16 + 4-10=7+9-8二20-16 + 13 =18 + 1 - 10=11-5-5 =14 + 8-12 =6 + 16-8=11 + 6 + 3 =7+9+4=9-6 + 16=4-3+2=15 -

30、12 + 3 =4-1 + 15 =8-5-3=16-1-1 =18 - 13 + 11 =19 + 4-18=4 + 13 + 1=4-2 + 14=11 + 16-20=7-1+1=8+2-7=15 - 13 + 6=20-6-2 =14 + 1 - 13 =18-6-12 =16-3- 10=9+8-4=16-8 + 3 =19 + 5 - 13 = 17-6 + 8=20 - 20 + 18=19-9 + 6=2 + 14-15 =10 + 13 -10=19 - 14 + 5=11 + 1 + 8=11 + 6 + 1 = 7+9-4=8 + 9-14=10 + 9-9=19-9 +

31、 7=19 + 3 - 16= 18-4 + 1=13-1-9=12 - 11 + 18=9-7+4二17-6-4=2+8+8=7 + 9 - 15 =10-3 + 3二19-4-11=5 + 18-15 =18 - 16 + 10=2 + 3 + 14=10-7 + 5 =17 -10 + 2=15-7 + 6=5 + 13 - 14=6+4+5=5-2 + 13二9 + 16-10=5 + 9-13=6+1-2=10 + 15 - 5二14 + 14-12 =15 - 14 + 16=8+5-2二13 + 4-4二15 + 4-8二1 + 2 + 11 =8+9-5二18 + 11-11=

32、8-1 + 13 =10 + 10-6=19-18 + 8=20-7-2=14-12 + 4=10 + 8 + 1=2-1 + 14=7+7-4二19 + 2-5 =16-5-6=6-2+4=17 + 5 - 12=9+6+3=15 - 14 + 6=7 + 17-16=7 -5 + 15 =13-1 + 6=1+9-4=4 + 18-10=20-14-1 =2 + 6 + 12 =20 + 6-14=13 + 9-12 =13 -1 + 4=2+7+6=8-2+9二13-4-9=20 - 13 + 7=12 + 3-3 =19-6 + 6=18 -16 - 2=3 + 12 + 5=5-5+

33、1=3 + 11 + 2=3-1 + 14=13-2 + 4二8+6+1=19-9-7=14-12 + 13 =20-13 + 12 =20-4-10=18 -13-4=4 + 3 + 10=10-2 + 1=8+8-1=8 + 20 - 20=14-6 + 9=7 + 15-9二13 - 11 + 10=4+1+1=14-3 + 4=18 + 5-6=20-13 + 6=10-6 + 7=14-12 + 7=12 + 7-18=17 + 4-6=20-17 + 17=12 + 2 + 6=8 + 9-17=9 + 9-14=17-3-2 =17-17 + 2 =I + 6 + 10=2+7-

34、4=4-1 + 13 二7+4-1二II + 4 + 5 =11-9 + 12=12-8 + 13 =7+5-7二11-7 + 7=18 - 18 + 12=5-5 + 12 =17-7-2 =17 -10 + 9=12-5 + 9=2 + 17-13 =20 + 1 - 20=16 -11-4=8-1-7=20-1-7=2+6+6=6 + 10 + 2 =18 + 6-12 =7-1-1=16-7-4=16-3-3 =2 + 12 + 2 =16-5-11=15-9-6=7-1+8=7 + 13 - 15 =2 + 10 + 7=15 + 1-9=1 + 2 + 13=9-1+3=20-1-

35、2 =4-2+4二3 + 18-16=10-8 + 1 =5 + 15 - 3二20-5-8=11-9 + 15=8-3+7=10 + 19-9=19-7-11 =20 - 14 - 2=14 + 14-16=11 + 2 - 5二18-8 + 3 =4 + 13-6=16-7 + 1 =18-16 + 5 =19 - 14 - 4=5-1 + 10=7 + 20-12 =2+2+2=9-5 + 14=2-2 + 14=12 + 6 + 1=15 - 13 + 17=8+2+4=10-2-2 =16-3-5=20-10 + 10=18-13 + 5=15-1-13 =2-2 + 17=19 +

36、 11-20=13 -13 + 1=9+1-5二18 + 8-7=12-2-6=13 + 7-10=10 + 1 + 5=11 + 5-8=16-9 + 1=19 + 1-4=18-9 + 7=8 + 10-4=11 + 17-19=10-6-3 =4+7+9=15 + 1-3 =15-8-5 =10 + 3 + 5 =4 + 16-15 =5-2 + 10=8-1+1=10 + 2 + 4=15-4-6=1 + 14-10=7+7+2=8-5 + 14=10 + 7-13 =9-9 + 1=8 + 5 - 11=20-19 + 6=4+6+7=9+9-8二6+8+5=16 + 15 - 12

37、=10 + 2 + 8=3+5-7=10-3 + 1=9 + 17-13 =19-14 + 14=13 + 3 - 11=4+7+5=13 - 12 + 10=10-6-2=8-2+5=15-1-6=9-7 + 17=11 + 2-2 =11-2-2 =18 + 6-11=10-8 + 13 =17-3 + 2 =12 - 12 + 12=20 -17 + 1 =18 - 13 + 9=2+2+4=20-8-10=16 + 13 - 12=1 + 10 + 7=8 + 15 - 12 =12 + 11 - 17=13-7 + 7=12 + 12 - 14=7+8+1=10-9 + 13 =20

38、-14 + 10=20-8-8=19-5-3 =10-9 + 17=5 + 11 + 4=8-4+8二7-7 + 14=14 + 9-12 =7-3 + 13 =20-9-2 =1-1 + 10=18-5- 12=17 - 10 - 5二18-7 + 3 =10 + 4-7=18 - 1 - 15 =16 + 1 + 2 =6+8-1二18-11-3 =20-13 + 10=13 + 6-15 =20 - 10 - 4=18 -10 + 7=7 + 15 - 18=15 - 13 + 4=17 + 10-8=16-7-7=15 -12 + 1=3 + 18-8=7-2+6=12 + 19-20

39、=7+3+2=9+2+7=11 + 4-13 =7 + 11-4=12 + 2-3 =20-15 + 9=16-12 + 15 =5 + 12 - 17=14-9 + 9=7+1+7=4 + 19-17=18-6-8=9+4-3二3 + 18-19=17-6-6=18-1-3 =11-3-3 =12-7-3 =12 + 9-4=18 -15 + 12 =14 + 4-11=10-4 + 1=8 + 7-11=10 + 7 + 3=17 - 14 + 17=19 -17 + 1=15-9 + 13 =15 + 10-19=10 + 11-8=18 - 18 + 18=12-5 + 8=11 +

40、19-17=19-5-2 =15-9-2 =18 + 3 - 17=18 -10 + 6=5 + 11 + 2=19 + 1 - 17=17 + 5 - 16=2 + 19-20二6 + 19-18=14-14 + 15 =20-14 + 8=20-6-6=7 + 10-2 =5 + 11 + 1=7 + 19-9=2+9+1=8+8-8二11-4 + 6=6+2+8=14 + 15 - 18=14-4 + 3二2 + 1 + 12 =19-18 + 12 =11 -10 + 1 =15 - 12 + 16=9 -4 + 4二8-6+6=12 + 16-16=18 - 17 + 17=4-4

41、+ 18=12 + 4-12 =1 + 20-3 =12 + 7-6=15 - 10 + 2=14 + 14-14=12 + 14-8=6 + 14-13 =9 + 19-15 =13 - 13 + 4=7+5+3=7+5+7=3+1-3=12 + 16-9=17 + 2 - 13 =20-5-3 =7-3-2=18-12 + 5 =11 + 1-2 =9+5-3=14 + 17-11=8 + 20-11二11-2 + 2 =13+4-1=1+7+7=20 - 14 - 4=18-7-11 =2+7+1=18-13 + 13 =4 + 10-3 =8+5+7=16 + 1 - 16=11 + 12 - 15 =10 + 16-12=6+8+4=6 + 12-1=11 + 8-19=9-9+9=1+3-2二4-1+2=20 - 10 - 6=16-3 + 4 =1 + 17-16=16-14 + 4=14 + 9-15 =