The Arbeitsbuch includes listening tasks (audio tracks on CD or via app). The answer key includes transcripts and solutions. Without the key, you may not be able to check listening comprehension.
Some workbook exercises directly mirror the Kursbuch . You can sometimes infer answers by re-reading the coursebook dialogues or grammar tables. This is slower but pedagogically beneficial. Das Neue Deutschmobil 2 Arbeitsbuch Antworten Pdf