22400 because the rule for rounding is to round based off of the number next to the place you want to round to. You're rounding to the nearest hundreds so you look at the tens place. If the number is 4 or less you round down, and if the number is 5 or more, you round up. The number in the tens place is 6 so you round up to get 22400. Hope that this answer and explanation help!