脱式计算.
(1)2400÷80+14×12
(2)420÷[(205-198)×4]
(3)63×73-63×63(4)25×44(5)57×19+57(6)85×(100+1)
网友回答
解:(1)2400÷80+14×12,
=30+168,
=198;
(2)420÷[(205-198)×4],
=420÷[7×4],
=420÷7÷4,
=60÷4,
=15;
(3)63×73-63×63,
=63×(73-63),
=63×10,
=630;
(4)25×44,
=25×4×11,
=100×11,
=1100;
(5)57×19+57,
=57×(19+1),
=57×20,
=1140;
(6)85×(100+1),
=85×100+85×1,
=8500+85,
=8585.
解析分析:(1)依据整数四则运算计算顺序解答,(2)依据除法性质解答,(3)(5)(6)运用乘法分配律解答,(4)化44=4×11解答.
点评:本题主要考查学生依据四则运算计算方法,以及正确运用简便算法解决问题的能力,注意计算的顺序.