(1.5+0.31+0.97)×(0.31+0.97+0.82)-(1.5+0.31+0.97+0.82)×(0.31+0.97)
=(1.5+0.31+0.97)×(0.31+0.97+0.82)-(1.5+0.31+0.97)×(0.31+0.97)－0.82×(0.31+0.97)
=(1.5+0.31+0.97)×(0.31+0.97+0.82－0.31-0.97)－0.82×(0.31+0.97)
=(1.5+0.31+0.97)×0.82－0.82×(0.31+0.97)
=(1.5+0.31+0.97--0.31-0.97)×0.82
=1.5×0.82
=1.23