题目内容
递等式计算,能简算的要简算.
| ( | |
解:(1)
×
+
×
,
=(
+
)×
,
=1×
,
=
;
(2)(
+
)×35,
=
×35+
×35,
=7+20,
=27;
(3)
×
-
×
,
=(
-
)×
,
=
×
,
=
;
(4)
+
×2,
=
+
,
=
;
(5)
×
+
×
,
=(
+
)×
,
=1×
,
=
;
(6)
×(
-
),
=
×
,
=
.
分析:(1)(2)(3)(5)运用乘法分配律简算;
(4)先算乘法,再算加法;
(6)先算小括号里面的减法,再算括号外的乘法.
点评:本题考查了四则混合运算,注意运算顺序和运算法则,灵活运用所学的运算定律进行简便计算.
=(
=1×
=
(2)(
=
=7+20,
=27;
(3)
=(
=
=
(4)
=
=
(5)
=(
=1×
=
(6)
=
=
分析:(1)(2)(3)(5)运用乘法分配律简算;
(4)先算乘法,再算加法;
(6)先算小括号里面的减法,再算括号外的乘法.
点评:本题考查了四则混合运算,注意运算顺序和运算法则,灵活运用所学的运算定律进行简便计算.
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