×3 ×17+×17 20×() 24×() ()
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解:(1)××=;
(2)+×3,
=+,
=;
(3)×+×,
=×(+),
=×1,
=;
(4)×-,
=-,
=;
(5)×17-×17,
=(-)×17,
=1×17,
=17;
(6)---,
=-(++),
=-1,
=-;
(7)20×(-+),
=20×-20×+20×,
=5-4+10,
=11;
(8)24×(-+),
=24×-24×+24×,
=20-18+16,
=18;
(9)×+×
=×(+),
=×,
=;
(10)-(-)
=-+,
=.
解析分析:(1)约分计算;
(2)先算乘法,再算加法;
(3)(5)(7)(8)(9)运用乘法分配律简算;
(4)先算乘法,再算减法;
(6)(10)运用减法的性质简算.
点评:此题考查了四则混合运算,注意运算顺序和运算法则,灵活运用所学的运算定律进行简便计算.