Teacher: In this task you will be given an arithmetic operation in Italian and you have to find its answer. The operations 'addition' and 'subtraction' have been replaced with their italian translations i.e you need to perform addition when you see 'aggiunta' and subtraction in case of 'sottrazione'.
Teacher: Now, understand the problem? If you are still confused, see the following example:
10 sottrazione 7
Solution: 3
Reason: Here, 'sottrazione' represents the subtraction operation. So, the answer is 3 (10-7=3).

Now, solve this instance: 6911 aggiunta 233 sottrazione 7837 sottrazione 1425 sottrazione 2575 sottrazione 9728 aggiunta 1351 aggiunta 5509 sottrazione 9299
Student:
-16860