(1) 9.8-3.27+12.31=10-0.2-3-0.27+12+0.31=(10-3+12)-(0.2+0.27-0.31)=18.84(2) 6.72-3.38-0.62=6.72-(3.38+0.62)=6.72-4=2.72(3) 97.3+(7.3+19.5)=100-2.7+7.3+20-0.5=(100+20)+7.3-(2.7+0.5)=124.118.54-3.7-2.3-8.54=(18.54-8.54)-(3.7+2.3)=4