脱式计算,能简算的要简算. ÷9+×()×+(+)×4817×(+)×15++++.
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解:(1)÷9+×,
=×+×,
=×(+),
=×1,
=;
(2)()×+,
=×-×+,
=-+,
=+(-),
=+,
=;
(3)(+)×48,
=48××48+×48,
=24-16+12,
=8+12,
=20;
(4)17×(+)×15,
=(17×15)×(+),
=(17×)×15+(15×)×17,
=2×15+1×17,
=30+17,
=47;
(5)++++,
=-+-+-+-+-,
=-,
=.
解析分析:(1)先把除法变成乘法,再运用乘法分配律简算;
(2)先运用乘法分配律简算,再运用加法结合律简算;
(3)运用乘法分配律简算;
(4)先把17×15结合在一起,再运用乘法分配律简算;
(5)=-,=-…由此化简求解.
点评:完成本题要注意分析式中数据,运用合适的简便方法计算.