Doing exercises in the seventh grade math textbook is like rushing forward and can't slow down. The following is the answer reference of the seventh grade mathematics textbook of Beijing Normal University, which I carefully arranged for you, for reference only.

The answer reference (1) of the seventh grade mathematics textbook of Beijing Normal University Edition has 42 pages.

( 1)-2; (2)8; (3)-8(4)2; (5)0; (6)-7; (7)7; (8)- 12; (9)20.

Beijing Normal University Edition Seventh Grade Mathematics Textbook Answer Reference (2) Exercise 46

Solution: (1) 33.1-(-22.9)+(-10.5) = 33.1+22.9-10.5 = 56-/kloc-.

(2)(-8)-(- 15)+(-9)-(- 12)=-8+ 15-9+ 12=-8-9+ 15+ 12=- 17+27= 10;

(3) 1/2+(- 2/3)-(-4/5)+(- 1/2)= 1/2-2/3+4/5- 1/2= 1/2- 1/2-2/3+4/5=- 10/ 15+ 12/ 15=2/ 15;

(4) 10/3+(- 1 1/4)-(-5/6)+(-7/ 12)= 10/3- 1 1/4+5/6-7/ 12=40/ 12-33/ 12+ / kloc-0/0/ 12-7/ 12=(40-33+ 10-7)/ 12= 10/ 12=5/6.

The answer reference of the seventh grade mathematics textbook published by Beijing Normal University (3) Exercise 2.8

Solution: (1) 27-28+(-7)-32 = 27-18-7-32 = 27-7+(-18-32) = 20+(-50).

(2) 1/3+(- 1/5)- 1+ 2/3= 1/3+2/3+(- 1/5)+(- 1)= 1+(- 1/5)+(- 1)=- 1/5;

(3)0.5+(- 1/4)-(-2.75)+ 1/2=0.5-0.25+2.75+0.5=0.5+0.5-0.25+2.75= 1-0.25+2.75= 1+2.75-0.25=3.75-0.25=3.5;

(4)(-2/3)+(- 1/6)-(- 1/4)- 1/2=-4/6- 1/6+( 1/4- 1/2)=-5/6- 1/4=- 10/ 12-3/ 12=- 13/ 12.

problem solving

2. Solution: 20-3-10-3+2+9+3 =18 (ten thousand people).

A: Compared with September 30th,1October 7th, 65438 passenger flow increased180,000.

3. Solution: Take 40kg as the standard weight, the number of kilograms exceeding the standard weight is positive, and the number of kilograms below the standard weight is negative.

40x 10+(7+8-2.5+2+5+0- 1.5-5.5-2+2.5)？ 10=(400+ 13)? 10=4 1.3 (kg).