1. 5-7+4+6= -2+4+6= 8
2. -4-2+3-(2-9+1)= -6+3-(-6)= -3+6= 3
3. 7-(12+4)-(21-25)-(-8)= 7-16+4+8= -9+4+8= 3
4. 13+12-(-7-9+12)-(3-18)=25+4-(-15)=29+15=44
5. -12-(4-9)-(-7-5)-11= -12+5+12-11= -6
6. 22-28+6+6= 6
7. -23+20-(12-7)-8= -3-5-8= -16
