计算下面各题,能简算的要用简便方法计算. 23.4-5.7-4.3(467+36×3)÷2325×50×4×646×16+16×5414.9+3.7+5.1+6.33800÷(1280-72×15)1800-800÷25×1665×10299×48+48.
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解:(1)23.4-5.7-4.3,
=23.4-(5.7+4.3),
=23.4-10,
=13.4;
(2)(467+36×3)÷23,
=(467+108)÷23,
=575÷23,
=25;
(3)25×50×4×6,
=(25×4)×(50×6),
=100×300,
=30000;
(4)46×16+16×54,
=(46+54)×16,
=100×16,
=1600;
(5)14.9+3.7+5.1+6.3,
=(14.9+5.1)+(3.7+6.3),
=20+10,
=30;
(6)3800÷(1280-72×15),
=3800÷(1280-1080),
=3800÷200,
=19;
(7)1800-800÷25×16,
=1800-32×16,
=1800-512,
=1288;
(8)65×102,
=65×(100+2),
=6500+130,
=6630;
(9)99×48+48,
=(99+1)×48,
=100×48,
=4800.
解析分析:(1)运用减法的性质简算;(2)先算括号内的乘法,再算括号内的加法,最后算括号外的除法;(3)运用乘法交换律与结合律简算;(4)(9)运用乘法分配律简算;(5)运用加法交换律与结合律简算;(6)先算括号内的乘法,再算括号内的减法,最后算括号外的除法;(7)先算除法和乘法,再算减法;(8)把102看作100+2,运用乘法分配律简算.
点评:此题考查了小数、整数的四则混合运算,注意运算顺序和运算法则,灵活运用所学的运算定律简便计算.