0.125×32×2.5
6.7×0.9+3.3×0.9
(
-
+
)÷
18.7×98+18.7+18.7
0.65×14+87×65%-
.解:(1)0.125×32×2.5,=0.125×8×4×2.5,
=(0.125×8)×(4×2.5),
=1×10,
=10;
(2)6.7×0.9+3.3×0.9,
=(6.7+3.3)×0.9,
=10×0.9,
=9;
(3)(
-
+
)÷
,=(
-
+
)×24,=
×24-
×24+
×24,=16-12+4,
=4+4,
=8;
(4)18.7×98+18.7+18.7,
=18.7×98+18.7×2,
=(98+2)×18.7,
=100×18.7,
=1870;
(5)0.65×14+87×65%-
,=0.65×14+87×0.65-0.65,
=0.65×(14+87-1),
=0.65×100,
=65.
分析:(1)把32分解成8×4,然后运用乘法结合律简算;
(2)运用乘法分配律简算;
(3)先把除法变成乘法,再运用乘法分配律简算;
(4)先把根据乘法的意义,把2个18.7的和变成18.7×2,再运用乘法分配律简算;
(5)先把分数、百分数化成小数,再运用乘法分配律简算.
点评:此题是考查四则混合运算,要仔细观察算式的特点,灵活运用一些定律进行简便计算.