Scientific notation questions?

Question

i need some help with these problems:

(-4.12 x 10*-4) (7.33 x 10*12)

1.0 x 10*14 / 4.2 x 10*-6

7.85 x 10*26 / 6.02 x 10*23

(6.02 x 10*23) (-5.11 x 10*-27) / -8.23 x 10*5

thanks =].

Answer 1

- 3.02 x 10^9

2.4 x 10^19

1.31 x 10^3

3.73 x 10^-9