①
÷(
-
)×(
-
) ②9
×4.25+4
×
③
-0.6×(
-1.75)④(
-
)÷(13×
)解:①
÷(
-
)×(
-
),=
÷
×
,=
×3×
,=
;②9
×4.25+4
×
,=(9
+
)×4.25,=10×4.25,
=42.5;
③
-0.6×(
-1.75),=
-(0.6×
-0.6×1.75),=
-(1.45-1.05),=0.75-0.4,
=0.35;
④(
-
)÷(13×
),=
÷
,=
.分析:①先算括号里面的,再算括号外面的乘除法;
②③可据乘法分配律进行计算;
④先算括号里面的,再算括号外面的除法.
点评:考查了运算定律与简便运算,四则混合运算.注意运算顺序和运算法则,灵活运用所学的运算律简便计算.