解题思路:(1)首先把3.2分成8×0.4,然后根据乘法交换律和结合律简算即可;
(2)根据加法交换律和减法的性质简算即可;
(3)(4)(6)根据乘法分配律简算即可;
(5)根据加法交换律和结合律简算即可.
(1)2.5×12.5×3.2
=2.5×12.5×8×0.4
=(2.5×0.4)×(12.5×8)
=1×100
=100
(2)18.72-3.34-1.66-1.72
=18.72-1.72-(3.34+1.66)
=17-5
=12
(3)1.25×17.6+36÷0.8+2.64×12.5
=1.25×17.6+36×1.25+26.4×1.25
=1.25×(17.6+36+26.4)
=1.25×80
=100
(4)([5/8]+[1/27])×8+[19/27]
=[5/8]×8+[1/27]×8+[19/27]
=5+[1/27]×(8+19)
=5+1
=6
(5)(+4.8)+(-14)+(-6)+(+15.2)
=(4.8+15.2)-(14+6)
=20-20
=0
(6)[567+345×566/567×345+222]
=[567×345−345+567/567×345+222]
=[567×345+222/567×345+222]
=1
点评:
本题考点: 小数四则混合运算;运算定律与简便运算;分数的四则混合运算.
考点点评: 此题主要考查了加法、乘法运算定律和减法的性质在简算中的应用.