解题思路:①0.25×4×0.8×0.125,运用乘法结合律简算;
②5.5×7.3+2.7×5.5,运用乘法分配律简算;
③31.7-0.5×0.7-1.65,先算乘法,再根据减法的运算性质简算;
④8.4×0.6+0.74,先算乘法,再算减法.
①0.25×4×0.8×0.125
=(0.25×4)×(0.8×0.125)
=1×0.1
=0.1;
②5.5×7.3+2.7×5.5
=5.5×(7.3+2.7)
=5.5×10
=55;
③31.7-0.5×0.7-1.65
=31.5-(0.35+1.65)
=31.5-2
=29.5;
④8.4×0.6+0.74
=5.04+0.74
=5.78.
点评:
本题考点: 运算定律与简便运算;小数四则混合运算.
考点点评: 此题考查的目的是理解掌握小数四则混合运算的顺序及它们的计算法则,并且能够灵活选择简便方法进行计算.