In 2010 the continent of South America had a population of 395,280,204. Which of the following is the closest estimate of this number
Round to the nearest power of 10
3 x10^8
4×10^7
4x10^8
4x10^9
Well 4 x 10⁸ is 400, 000, 000 which is the closest to 395, 280, 204. For future reference, the number of powers the 10 is raised to is the number of zeros it will have.
