脱式计算.
1×+×6??????????????????????????6.5×+0.24×4.5-6÷251+2+3+4?????????????????????12÷-[6+3×(3-2)]61×+71×+81×??????????????????????7×0.6+×7)÷÷.
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解:(1)1×+×6
=(1+6)×,
=8×,
=6;
(2)6.5×+0.24×4.5-6÷25
=6.5×0.24+0.24×4.5-0.24,
=(6.5+4.5-1)×0.24,
=10×0.24,
=2.4;
(3)1+2+3+4
=(1+2+3+4)+(++++),
=10+(1-+-+-+-)÷2,
=10+÷2,
=10+,
=10;
(4)12÷-[6+3×(3-2)]
=×-[6+×],
=14-[6+1],
=14-8,
=6;
(5)61×+71×+81×
=×+×+×,
=51+61+71,
=183;
(6)(7×0.6+×7)÷÷.
=(7×+×7)××,
=(7+7)×××,
=15×××,
=35.
解析分析:算式(1)(2)(6)可根据乘法分配律计算;算式(3)可根据分数巧算公式:=(-)÷2进行计算;算式(4)(5)根据四则混合运算的运算顺序计算即可:先算乘除,再算加减,有括号的要先算括号里面的.
点评:完成本题要认真分析式中数据的特点及内在联系,然后运用合适的方法进行计算.