Ireally need with these math problems!

A) 2.025 x 10^14 kilometers / 225 million years

B) 2.25 × 10^8

C) 2.025 x 10^14 kilometers / 2.25 x 10^8 years

D) 2.025 x 2.25 = .9

E) 10^14 - 8 = 10^6

F) .9 x 10^6

Notes:
To write in scientific notation, move the decimal place over until there is only 1 number outside of it. (25,000 now equals 2.5) Then count how many spaces you moved over (25,000 moved over three zeros, and the five. That is 4 places) that is what you use to put over the 10 (2.5 x 10^4 = 25,000)

Element 17 is chlorine it is a group 7 element(halogen) and belongs to period 3 of the periodic table