题目内容
递等式计算,能简便的用简便方法.
| 49× | ||
| ( | ( |
解:(1)
×
+
×
,
=(
)×
,
=1×
,
=
;
(2)
×
×16,
=
×16×
,
=10×
,
=2
;
(3)49×
,
=48×
+1×
,
=11+
,
=11
;
(4)
×12+
,
=12×(
),
=12×1,
=12;
(5)(
+
)×12×35,
=
×12×35+
×12×35,
=9×35+12×7,
=315+84,
=499;
(6)(
+
+
)×48,
=
×48+
×48+
×48,
=42+8+32,
=82.
分析:(1)(3)(4)(5)(6)运用乘法分配律解答,
(2)运用乘法交换律解答.
点评:完成本题要注意分析式中数据,运用合适的简便方法计算.
=(
=1×
=
(2)
=
=10×
=2
(3)49×
=48×
=11+
=11
(4)
=12×(
=12×1,
=12;
(5)(
=
=9×35+12×7,
=315+84,
=499;
(6)(
=
=42+8+32,
=82.
分析:(1)(3)(4)(5)(6)运用乘法分配律解答,
(2)运用乘法交换律解答.
点评:完成本题要注意分析式中数据,运用合适的简便方法计算.
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