Someone recently asked me about test 2, question 27 in Cambridge IELTS 7. The answer to this question is "1882 to 1883", but the student thought he heard "1892 to 1893". Students in my classes have often made the same mistake.
So, why do people hear 1892 when the speaker says 1882?
The reason is that you hear the letter 'n' at the end of '18' e.g. eightee-n-eighty-two. If the speaker is talking quickly, it might sound like the 'n' is the first letter of the number that comes after 18.
However, you should ignore this 'n' because it is simply the last letter in the word "eighteen". Instead, you need to hear the "ei" vowel sound in "eighty" instead of the "ai" sound in "ninety". For me, the difference between 1882 and 1892 is very clear, because I hear a completely different vowel sound.