一、填空题1.(-9)+(-5)+(-3)省略加号后写为__.2.5-7-9+3读作__的和.3.(-10)+(+2)-(-20)-(+3)省略括号写为__.4.运用加法交换律,式子5-7可以写成__.5.当a=-3,b=2,c=-2时,代数式(a-b)+(b-c)+(c-a)的值等于__.6.若a=3,且a+b=-1,则b=__.7.计算:(-28)+(-12)-(-18)+(+24)-(+32)=__.8.有理数在数轴上的位置如图: 则a-a+b+c-a+b+c= First, fill in the blank questions 1. (-9) + (-5) + (-3) omit the plus sign written as __. 2.5-7-9 + 3 read as __ and .3. (-10) + (+2)-(-20)-(+3) Omit parentheses are written as __.4. Using the additive commutative law, Equations 5-7 can be written as __.5. When a=-3, b=2, When c=-2, the algebraic expression (ab)+(bc)+(ca) is equal to __.6. If a=3 and a+b=-1, then b=__.7. Calculation: (- 28) +(-12)-(-18)+(+24)-(+32)=__.8. The position of rational numbers on the number axis is shown as: a-a+b+c-a+b+c =