Question

10+{-12+[5-(1-9)]-7}

Answer 1

10+{-12+[5-(1-9)]-7}=
10+{-12+[5-(-8)]-7}=
10+{-12+[5+8]-7}=
10+{-12+13-7}=
10+{-6}=4

Answer 2

 Boa Noite !!!!

10+{-12+[5-(1-9)]-7}=

10+{-12+[5+8]-7}=

10+{-12+13-7}=

10-6=

4