题目内容
递等式计算,能简便的用简便方法.
|
|
49×
| ||||||||||||||
|
(
|
(
|
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.
(2)运用乘法交换律解答.
解答: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.
| 4 |
| 9 |
| 5 |
| 13 |
| 5 |
| 13 |
| 5 |
| 9 |
=(
| 4 |
| 9 |
| 5 |
| 9 |
| 5 |
| 13 |
=1×
| 5 |
| 13 |
=
| 5 |
| 13 |
(2)
| 5 |
| 8 |
| 2 |
| 7 |
=
| 5 |
| 8 |
| 2 |
| 7 |
=10×
| 2 |
| 7 |
=2
| 6 |
| 7 |
(3)49×
| 11 |
| 48 |
=48×
| 11 |
| 48 |
| 11 |
| 48 |
=11+
| 11 |
| 48 |
=11
| 11 |
| 48 |
(4)
| 34 |
| 35 |
| 12 |
| 35 |
=12×(
| 34 |
| 35 |
| 1 |
| 35 |
=12×1,
=12;
(5)(
| 3 |
| 4 |
| 1 |
| 5 |
=
| 3 |
| 4 |
| 1 |
| 5 |
=9×35+12×7,
=315+84,
=499;
(6)(
| 7 |
| 8 |
| 1 |
| 6 |
| 2 |
| 3 |
=
| 7 |
| 8 |
| 1 |
| 6 |
| 2 |
| 3 |
=42+8+32,
=82.
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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