Question

- {+2- [+15-23*2+3-4] - [-28+15-2] - (+5-3)-7}=

Answer 1

= - {2-[15-23×2+3-4] - [-28+15-2]-(+5-3)-7} =
= - {2- [15-46-1] - [-30+15]-2-7}=
= - {2-[15-47]+5-9}= - {2+32+5-9}=
= - {39-9}= -30