12.34减4.54减5.46简便,0.98乘7.2简便 1.02乘6.5简便 （8减0.8）乘1.25简便 18.8乘101减18.8简便
问题描述：
12.34减4.54减5.46简便,0.98乘7.2简便 1.02乘6.5简便 （8减0.8）乘1.25简便 18.8乘101减18.8简便
5.12加5,12乘9 简便 3.15乘1.6加1.85乘1.6简便
答
12.34-4.54-5.46=12.34-(4.54+5.46)=12.34-10=2.340.98×7.2=(1-0.02)×7.2=1×7.2-0.02×7.2=7.2-0.144=7.0561.02×6.5=(1+0.02)×6.5=1×6.5+0.02×6.5=6.5+0.13=6.63(8-0.8)×1.25=8×1.25-0.8×1.25=10-1=918.8...