3.9*9.9+0.39=?的简便算法是什麽
问题描述:
3.9*9.9+0.39=?的简便算法是什麽
答
3.9×9.9+0.39
= 3.9×9.9+3.9×0.1
= 3.9×(9.9+0.1)
= 3.9×10
= 39