2条数学简算题不会

81.5*15.8+81.5*51.8+67.6*18.5
=81.5×（15.8+51.8）+67.6×18.5
=81.5×67.6+67.6×18.5
=67.6×（81.5+18.5）
=67.6×100
=6760

53.5*35.3+53.5*43.2+78.5*46.5
=53.5×（35.3+43.2）+78.5×46.5
=53.5×78.5+78.5×46.5
=78.5×（53.5+46.5）
=78.5×100
=7850

81.5*15.8+81.5*51.8+67.6*18.5 53.5*35.3+53.5*43.2+78.5*46.5
=81.5*（15.8+51.8）+67.6*15.5
=81.5*67.6+67.6*15.5
=67.6*（81.8+15.5）
=67.6*100
=6760

53.5*35.3+53.5*43.2+78.5*46.5
=53.5*（35.3+43.2）+78.5*46.5
=53.5*78.5+78.5*46.5
=78.5*（53.5+46.5）
=78.5*100
=7850