21×(9.3-2.4)+6.9 简便方法计算
问题描述:
21×(9.3-2.4)+6.9 简便方法计算
答
21×(9.3-2.4)+6.9=21×6.9+6.9=20×6.9+2×6.9=138+13.8=151.8
21×(9.3-2.4)+6.9 简便方法计算
21×(9.3-2.4)+6.9=21×6.9+6.9=20×6.9+2×6.9=138+13.8=151.8