No.2 student's score: 87+ 10=97 points;

No.3 student's score: 87+8=95 points;

No.4 student's score: 87+5=92 points;

No.5 student's score: 87- 15=72 points;

No.6 student's score: 87- 1=86 points;

No.7 student's score: 87+0=87 points;

No.8 student's score: 87+8=95 points;

Grade of No.9 student: 87+13 =100;

Score of student 10: 87-6=8 1,

∴ The lowest score is 72, and the highest score is 100;

(2)∵ The lowest score is 72, and the highest score is 100.

100-72 = 28 points;

(3) The average score of class (2) in seven years is 87 points.

∴ 10 total score of students = 87×10+(-2+10+8+5-15-1+8+13-6).

(4) The total score of students in this group 10 is 890.

∴890÷ 10=89>87,(89-87)×2× 10=40,

∴ 10 students won awards in this group and * * * awarded 40 books.