问题标题:
【1.48×15的简便算法2.35×24的简便算法3.840÷12的简便算法4.540÷45的简便算法】
问题描述:

1.48×15的简便算法2.35×24的简便算法3.840÷12的简便算法4.540÷45的简便算法

曹敬回答:
  8×15   =4×2×15   =4×30   =120   2.35×24   =2.35×2×12   =4.7×12   =(5-0.3)×12   =5×12-0.3×12   =60-3.6   =56.4   3.840÷12   =0.96×4÷(3×4)   =0.96÷3   =0.32   4.540÷45   错了   是4.545÷45   =(4.5+0.045)÷45   =4.5÷45+0.045÷45   =0.1+0.001   =0.101
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