I am working my way through Italian 1 and just finished the lessons on numbers. Fluenz says that when 3 is at the end of the number, one adds this accent – ` – (e.g., ventitrè). However, when I was looking at Wiktionary's Italian Numbers appendix, I noticed they have the ´ accent (ventitré). Can anyone explain the discrepancy? Which one of these is correct, or are they both acceptable?