计算下面各题,能简算的要简算.?????
0.89×100.1????????????????????
146.5-(23+46.5)
5.83×2+4.27??????????????????
(45.9-32.7)÷8÷0.125.
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解:0.89×100.1,
=0.89×100+0.89×0.1,
=89+0.089,
=89.089;????????????????????
146.5-(23+46.5),
=146.5-46.5-23,
=100-23,
=77;
5.83×2+4.27,
=11.66+4.27,
=15.93;??????????????????
(45.9-32.7)÷8÷0.125,
=13.2÷(8×0.125),
=13.2÷1,
=13.2.
解析分析:小数、分数的四则混合运算同整数的四则混合运算类似,先算乘除,后算加减,有括号的先算括号内的.
运用乘法结合律、加法交换律可使运算简便.
点评:此题考查了小数的四则混合运算和运算定律与简便运算.括号前是减号(或除号),去掉(或加上)括号,括号内的数字变号.