Question

81.5*15.8+81.5*51.8+67.6*18.5 (速算) 53.5*35.3+53.5*43.2+78.5*

Answer 1

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