This is not a homework question, but it is from a book.... The book asks: In a nuclear chemistry experiment, an alpha particle is found to have a velocity of 14,285 m/s. Convert this measurement into miles/hour. I want to verify the correct way to do this, and I also have a question about the decimal point relocating. What I did (first): 14,285 meters per second * 3600 seconds in an hour = 51426000 51426000 / 1609.344 meters per mile = 31961.467 mph The book says the right answer is: 8.2796 x 10^10 However, when I google " 14,285 meters per second to miles per hour," Google's converter agrees with me... But if I do: 14,285 meters * 1 mile * 60 sec * 60 min / 0.000621371 * 1 sec * 1 min I get 82762150148.62296438 Which is almost the same as the book. Except the book has the decimal between the 8 and the 2 and gets 8.2796 instead of 8.2762 which I presume is because they're omitting insignificant numbers during calculation, but I still don't understand how the decimal got moved between the 8 and the 2 while mine is in middle.... My questions are: Which way is correct to convert this? And also, more importantly, why does the book move the decimal between the 8 and the 2?