1) -7264+ (1543 +7264)
=-7264+1543+7264
=(-7264+7264)+1543
=0+1543
=1543
2) (144-97) - 144
=144-97-144
=(144-144)-97
=0-97
=-97
3) (-145)-(18-145)
=-145-18+145
=(-145+145)-18
=0-18
=-18
4) 111+ (-11+27)
=111-11+27
=100+27
=127
5) (27+514) - (486-73)
=27+514 - 486 + 73
=(27+73)+(514-486)
=100+28
=128