Simplify the following expression:
1-1+2-2+3-3+-1-1+-2-2+-3-3
=111+122+133+-111+-122+-133
=11+14+127-11+14-127
=14+14
=24
=12
Properties of Exponents:
am·an=am+n
aman=am-n
amn=am·n
ab-n=ban
a0=1
2