令a=0.12+0.13+0.14
原式=(0.11+a)(a+0.15)-(0.11+a+0.15)a
=(0.11+a)a+0.15(0.11+a)-(0.11+a)a-0.15a
=0.15(0.11+a)-0.15a
=0.15×0.11+0.15a-0.15a
=0.0165
令a=0.12+0.13+0.14
原式=(0.11+a)(a+0.15)-(0.11+a+0.15)a
=(0.11+a)a+0.15(0.11+a)-(0.11+a)a-0.15a
=0.15(0.11+a)-0.15a
=0.15×0.11+0.15a-0.15a
=0.0165