7. 2+2
6. 解：＝
5. 解：原式=2+1-3+2 ……4分
=2 ……2分
4. 解：原式························································································ 2分
·········································································································· 5分
···················································································································· 6分
3. 解：原式········································································ 4分
································································································ 5分
······················································································································ 6分
2. 解：原式==
1. 解：原式=2+3-1-2=2
19. 20. 5 21. < 22. 23. 24. 25. 47
12. 13. 5 14. x≥2 15. 3 ． 16. ±4 17. ；18. (或+)；
1. 2. 1 3. 1 4. 5. 12 6. 6，4 7. 8. 4 9. 10. -1 11.
+2
＝
························································································ 2分
·········································································································· 5分
···················································································································· 6分
········································································ 4分
································································································ 5分
······················································································································ 6分
=
20. 5 21. < 22. 
23. 
24. 25. 47
13. 5 14. x≥2 15. 3 ． 16. ±4 17. 
；18. 
(或
+
)；
2. 1
3. 1 4. 
5. 12 6. 6，4 7. 
8. 4
9. 