Carry out the following operations, and express the answer with the appropriate number of significant figures:
Part A: 320.37-(61016.8/3.3)=?
Part B: [(290.1x10^5)-(1.100x10^3)]x2.8932=?
Part C: (0.0040x29000.0)+(2818x15)=?
Part D: 868x[1253-(3.87x108)]=?

I calculated all of them and I want you guys to help me check it. Thanks!
PA: -1.6x10^3
PB: 8.364x10^6
PC: 4.2x10^4
PD: 7.24x10^5