题目内容

16.计算题.(写出主要计算过程)
9999.9999÷6666.6666                 
20.15×37-201.5×1.9+2015×0.82
(1+0.23+0.34)×(0.23+0.34+0.65)-(1+0.23+0.34+0.65)×(0.23+0.34)

分析 (1)把原式化为(9×1111.111)÷(6×1111.1111),再计算即可;
(2)20.15×37=2015×0.37,201.5×1.9=2015×0.19,然后再根据乘法分配律进行简算;
(3)通过观察,此题中的数据很有特点,于是根据题中数据,设1+0.23+034=a,0.23+0.34=b,那么a-b=1+00.23+0.34-(0.23+0.34)=1.于是原式变为a×(b+0.56)-(a+0.56)×b=0.56×(a-b),把a-b=1,代入即可求出.

解答 解:(1)9999.9999÷6666.6666                 
=(9×1111.111)÷(6×1111.1111)
=(9÷6)×(1111.1111÷1111.1111)
=1.5.

(2)20.15×37-201.5×1.9+2015×0.82
=2015×0.37-2015×0.19++2015×0.82
=2015×(0.37-0.19+0.82)
=2015×1
=2015.

(3)设1+0.23+034=a,0.23+0.34=b,那么a-b=1+00.23+0.34-(0.23+0.34)=1.
(1+0.23+0.34)×(0.23+0.34+0.56)-(1+0.23+0.34+0.56)×(0.23+0.34)
=a×(b+0.56)-(a+0.56)×b
=ab+0.56a-ab-0.56b
=0.56a-0.56b
=0.56×(a-b)
=0.56×1
=0.56.

点评 解决这类问题,应注意审题,根据数字特点,运用运算技巧,巧妙解答.

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