5.38×0.84+0.362×8.4+0.84＝0.84×（5.38+3.62+1）＝0.84×10＝8.4
=5.38x0.84+3.62x0.84+0.84x1 =0.84x（5.38+3.62+1） =0.84x10=8.4
