解题思路:(1)(14)运用乘法结合律简算.
(2)(3)(4)(5)(8)运用乘法交换律与结合律简算.
(6)把598看作600-2,运用减法的性质简算.
(9)运用加法交换律与结合律简算.
(11)(12)(13)(15)运用乘法分配律简算.
(1)25×(40×32)
=(25×40)×32
=1000×32
=32000
(2)(5×7)×80
=(5×80)×7
=400×7
=2800
(3)8×14×125×6
=(8×125)×(14×6)
=1000×84
=84000
(4)16×25×5×4
=(16×5)×(25×4)
=90×100
=9000
(5)25×13×4
=(25×4)×13
=100×13
=1300
(6)2843-598
=2843-(600-2)
=2843-600+2
=2245
(7)4×8×25×125
=(4×25)×(8×125)
=100×1000
=100000
(8)259+468+741+532
=(259+741)+(468+532)
=1000+1000
=2000
(9)36×25
=9×4×25
=9×(4×25)
=9×100
=900
(10)12×15+12×35
=12×(15+35)
=12×50
=600
(11)31×128-28×31
=31×(128-28)
=31×100
=3100
(12)(25+250)×4
=25×4+250×4
=100+1000
=1100
(13)(125×125)×8
=125×(125×8)
=125×1000
=125000
(14)([7/12]-[1/5])×60
=60×[7/12]-[1/5]×60
=35-12
=23
(15)[4/7]×[6/13]+[3/7]×[6/13]
=([4/7]+[3/7])×[6/13]
=1×[6/13]
=[6/13]
点评:
本题考点: 运算定律与简便运算.
考点点评: 完成本题要注意分析式中数据,运用合适的简便方法计算.