أعط أجوبة - Italiano

صوّت الآنتم الإجـابة عليهسؤال لغوي بمعني (سؤال في اللغه المقصوده)
Why there is "aver" instead of "avere"?

In my book to learn Italian there was and excample "aver fame", "aver sete" or "aver sonno" why there is this version instead of avere? Is it an orthoraphy mistake or any exception?