4.9*6.8+0.51*6.8怎樣簡便

4.9*6.8+0.51*6.8怎樣簡便

4.9*6.8+0.51*6.8=(5-0.1)*6.8+(0.5+0.01)*6.8
=5*6.8-0.1*6.8+0.5*6.8+0.01*6.8
=34-0.68+3.4+0.068
=37.468-0.68
=36.788