题目内容
计算下面各题.
| 68×( | [1-( |
解:(1)
×4÷
,
=
×4×
,
=1;
(2)
+
×13,
=
×(13+1),
=
×14,
=3;
(3)
×
÷
×
,
=
×
×
×
,
=
;
(4)
-0.3×
,
=
-
×
,
=
-
,
=
;
(5)68×(
-
),
=68×
-68×
,
=60-18,
=42;
(6)[1-(
+
)]÷
,
=[1-
]÷
,
=
×4,
=
.
分析:(1)(3)把除法改为乘法,约分即可;
(2)(5)运用乘法分配律简算;
(4)把小数化为分数先算乘法,再算减法;
(6)先算小括号内的,再算中括号内的,最后算括号外的.
点评:此题考查了分数的四则混合运算,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.
=
=1;
(2)
=
=
=3;
(3)
=
=
(4)
=
=
=
(5)68×(
=68×
=60-18,
=42;
(6)[1-(
=[1-
=
=
分析:(1)(3)把除法改为乘法,约分即可;
(2)(5)运用乘法分配律简算;
(4)把小数化为分数先算乘法,再算减法;
(6)先算小括号内的,再算中括号内的,最后算括号外的.
点评:此题考查了分数的四则混合运算,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.
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