Calculate (4.2 ∙ 105) cm ∙ (4.0 ∙ 10-9) cm2.
!
1.7 -3
2 14
1.68

I believe the givens should be written in this manner,
                              (4.2 x 10⁵)(4.0 x 10⁻⁹)
To answer, we first multiply the bases 4.2 and 4 which will give us,
                                            16.8
Then, we multiply the multipliers by adding up the exponents of 10. This will give us the answer of,
                                      16.8 x 10⁻⁴
Then, the final answer would be 1.68 x 10⁻³.

Ithink they do have the same properties just in less quantities i think