Răspuns :
( - 7 + 12 - 15 ) : ( 8 - 17 + 7 ) =
( 5 - 15 ) : ( 8 - 17 + 7 ) =
- 10 : ( 8 - 17 + 7 ) =
- 10 : ( - 9 + 7 ) =
- 10 : - 2 =
5
( - 7 + 12 - 15 ) : ( 8 - 17 + 7 ) =
( 5 - 15 ) : ( 8 - 17 + 7 ) =
- 10 : ( 8 - 17 + 7 ) =
- 10 : ( - 9 + 7 ) =
- 10 : - 2 =
5