＝8.7*10.1*0.87＝8.7*1.01*10*0.87＝8.7*1.01*8.7＝8.7*8.7*1.01
=8.7×1.01×8.7=8.7²×1.01=(9-0.3)²×1.01=(9²-2×9×0.3十0.3²)×1.01=(81-5.4十0.09)×1.01=75.69×(1十0.01)=75.69十0.7569=76.4469
