早教吧 育儿知识 作业答案 考试题库 百科 知识分享

计算下面各题.(怎样简便怎样算)0.68×40.5×0.762.4×15-66.95÷6512.5×25×0.325.8×2.8+2.8+3.2×2.8.

题目详情
计算下面各题.(怎样简便怎样算)
0.68×40.5×0.7
62.4×15-66.95÷65
12.5×25×0.32      
5.8×2.8+2.8+3.2×2.8.
▼优质解答
答案和解析
①0.68×40.5×0.7
=(40.5×0.2)×(3.4×0.7)
=8.1×2.38
=(8+0.1)×2.38
=8×2.38+0.1×2.38
=19.04+0.238
=19.278

②62.4×15-66.95÷65
=936-1.03
=934.97

③12.5×25×0.32  
=(12.5×8)×(25×0.04)
=100×1
=100
    
④5.8×2.8+2.8+3.2×2.8
=2.8×(5.8+3.2)
=2.8×9
=25.2