2.9×0.45＋0.29×4.2＋0.029×13+怎样用简便方法计算?
0.029×0.45＋0.29×4.2＋0.029×13 =0.029×45＋0.029×42＋0.029×13 =0.029×（45＋42＋13） =0.029×100 =2.9