Answer:
The second one is correct.
Ten to third power is 1,000 :)
4,230, which is solved by multiplying both the questions and the students
The easiest way is if it doesn't need to be simplified. Multiply -2.105 by

. You get the fraction

. While this is technically the answer, you can simplify this down to

. Because 421 is a prime number, this can not be simplified any further. Therefore, the solution is

.

.