解:(3618÷18-145)×20,
=(201-145)×20,
=56×20,
=1120;
6÷
-
÷6,
=6×
-
×
,
=10-
,
=9
;
÷[
×(
+
)],
=
÷[
×
],
=
÷
,
=
×
,
=
;
125×25×32,
=125×25×(4×8),
=(125×8)×(25×4),
=1000×100,
=100000;
3.5×9.8+3.5×0.2,
=3.5×(9.8+0.2),
=3.5×10,
=35;
×
-
÷13,
=
×
-
×
,
=(
-
)×
,
=
×
,
=
.
分析:(3618÷18-145)×20,先計(jì)算小括號(hào)里的除法,再計(jì)算小括號(hào)里的減法,最后計(jì)算乘法;
6÷
-
÷6,先計(jì)算除法,最后計(jì)算減法;
÷[
×(
+
)],先計(jì)算小括號(hào)里的加法,再計(jì)算中括號(hào)的乘法,最后計(jì)算除法;
125×25×32,把32看作4×8,再根據(jù)乘法交換律和結(jié)合律進(jìn)行簡(jiǎn)算;
3.5×9.8+3.5×0.2,根據(jù)乘法分配律進(jìn)行簡(jiǎn)算;
×
-
÷13,根據(jù)乘法分配律進(jìn)行簡(jiǎn)算.
點(diǎn)評(píng):根據(jù)四則混合運(yùn)算的運(yùn)算順序,先算乘除,后算加減,有括號(hào)的先算小括號(hào)的,再算中括號(hào)的;能簡(jiǎn)算的要進(jìn)行簡(jiǎn)便計(jì)算.