How many kilometers is it from here to the airport?
Tips
grammar
多少 is used for any quantity (large or small). 几 is used when you expect a small number (usually under 10). 这个多少钱? vs 你有几个孩子?
mistakes
Two readings, two words. The question word is this one, with a neutral second syllable. Give 少 its full third tone and 多少 is a different word meaning the amount of something, or, in front of a verb, somewhat.