(7 x 10 x 10 x 10 x 10 = 70,000) (8 x 10 x 10 x 10 = 8,000) ignore zeroes for now then multiply 7 x 8 = 56, add zeroes back on, 560,000,000 and to put that in scientific notation you have to have a number between 1 and 10 and then from there you get 5.60000000 and count how many decimal places you had to move it to get it there, in this case it would be 8 so answer is B.
