(1+0.23+0.34)*(0.23+0.34+0.45)-(1+0.23+0.34+0.45)*(0.23+0.34)
令a=0.23+0.34
b=0.23+0.34+0.45
b-a=0.45
原式＝(1+a)*b-(1+b)*a
=b+ab-a-ab
=b-a
=0.45