The correct spelling of the phrase "doest a number" is actually "does a number". This phrase means "to cause trouble or confusion". The word "does" is pronounced /dʌz/ in IPA phonetic transcription, with the "o" sound being short and pronounced like the "u" in "butter". The word "number" is pronounced /ˈnʌmbər/ with the emphasis on the first syllable and the "u" sound again resembling the "u" in "butter". The correct spelling and pronunciation of words are important for effective communication.