题目内容
计算下面各题,能用简便算法的就用简便算法.
解:(1)
,
=
(
),
=
,
=
;
(2)(18+
)×
,
=18×
+
,
=14+
,
=14
;
(3)
,
=
(
),
=
1,
=
;
(4)
10-
,
=
(10-1),
=
9,
=8;
(5)
(
),
=
,
=
,
=
;
(6)
17,
=(
)×(
17),
=
7,
=1
.
分析:(1)运用乘法结合律解答,
(2)(3)(4)(5)运用乘法分配律解答,
(6)运用乘法交换律和结合律解答.
点评:解答本题要观察算式中各数的关系,选择并运用正确简便算法解答.
=
=
=
(2)(18+
=18×
=14+
=14
(3)
=
=
=
(4)
=
=
=8;
(5)
=
=
=
(6)
=(
=
=1
分析:(1)运用乘法结合律解答,
(2)(3)(4)(5)运用乘法分配律解答,
(6)运用乘法交换律和结合律解答.
点评:解答本题要观察算式中各数的关系,选择并运用正确简便算法解答.
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