(-64)+17+(-23)+68
=-64+17-23+68
=-87+85
=-2
63+72+(-96)+(-37)
=63+72-96-37
=135-133
=2
(-52)+24+(-74)+12
=-52+24-74+12
=-126+36
=-90
(-26)+52+16+(-72)
=-26+52+16-72
=68-98
=-30
(-64)+17+(-23)+68
=-64+17-23+68
=-87+85
=-2
63+72+(-96)+(-37)
=63+72-96-37
=135-133
=2
(-52)+24+(-74)+12
=-52+24-74+12
=-126+36
=-90
(-26)+52+16+(-72)
=-26+52+16-72
=68-98
=-30