Solution: The original formula =-25+34+ 156-65.

=(-25-65)+(34+ 156)

=-90+ 190

= 100

[-64]+ 17+[-23}+68

Solution: The original formula =-64+ 17-23+68.

=(-64-23)+( 17+68)

=-87+85

=-2

[-42]+57+[-84]+[-23]

Solution: The original formula =-42+57-84-23.

=(-42-84-23)+57

=- 149+57

=-92

63+72+[-96]+[-37]

Solution: Original formula =63+72-96-37.

=(63+72)+(-96-37)

= 135+(- 133)

=2

[-30 1]+ 125+30 1+[-75]

Solution: The original formula =-301+125+301-75.

=(-30 1+30 1)+( 125-75)

=0+50

=50

[-52]+24+[-74]+ 12

Solution: The original formula =-52+24-74+ 12.

=(-52+ 12)+(24-74)

=-40+(-50)

=-90

4 1+[-23]+[-3 1}+0

Solution: The original formula =4 1-23-3 1.

=(4 1-3 1)-23

=- 10-23

=-33

[-26]+52+ 16+[-72]

Solution: The original formula =-26+52+ 16-72.

=(-26+ 16)+(52-72)

=- 10+(-20)

=-30