$\left(+8\right)+\left(-13\right)-\left(-12\right)+\left(-17\right)-\left(-3\right)=$  

(a)  

 $-2+\left\{-17+12-\left(21+2\right)\right\}+9=$  

(a)  

 $8\div\left(3-5\right)-2\times\left[-3\times\left(1-4\right)-6\div\left(1-3\right)\right]=$  

(a)  

 $^3\sqrt{125}+\left[36\div\left(8-2\right)+2+\left(-3\right)^2\right]-9^0=$  

(a)  

 $^5\sqrt{-32}\div\left(-2\right)+\left(^3\sqrt{64}+2^0\right)^2-5^2=$  

(a)