题目内容
小小神算手.
|
42×(
|
| ||||||||||||||
|
|
35×
|
考点:分数的四则混合运算,运算定律与简便运算
专题:运算顺序及法则,运算定律及简算
分析:(1)直接约分计算即可;
(5)先算除法,再算减法;
其余各题利用乘法分配律简算.
(5)先算除法,再算减法;
其余各题利用乘法分配律简算.
解答:
(2)42×(
+
)
=42×
+42×
=24+10
=34;
(3)
×16+
×16
=(
+
)×16
=1×16
=16;
(4)
÷3+
×
=
×
+
×
=(
+
)×
=1×
=
;
(5)
÷3-
=
×
-
=
-
=
;
(6)35×
-35×
=35×(
-
)
=35×1
=35.
解:(1)
=
|
| 4 |
| 7 |
| 5 |
| 21 |
=42×
| 4 |
| 7 |
| 5 |
| 21 |
=24+10
=34;
(3)
| 3 |
| 5 |
| 2 |
| 5 |
=(
| 3 |
| 5 |
| 2 |
| 5 |
=1×16
=16;
(4)
| 1 |
| 6 |
| 5 |
| 6 |
| 1 |
| 3 |
=
| 1 |
| 6 |
| 1 |
| 3 |
| 5 |
| 6 |
| 1 |
| 3 |
=(
| 1 |
| 6 |
| 5 |
| 6 |
| 1 |
| 3 |
=1×
| 1 |
| 3 |
=
| 1 |
| 3 |
(5)
| 7 |
| 8 |
| 5 |
| 24 |
=
| 7 |
| 8 |
| 1 |
| 3 |
| 5 |
| 24 |
=
| 7 |
| 24 |
| 5 |
| 24 |
=
| 1 |
| 12 |
(6)35×
| 9 |
| 8 |
| 1 |
| 8 |
=35×(
| 9 |
| 8 |
| 1 |
| 8 |
=35×1
=35.
点评:分数混合运算的关键是搞清运算顺序,适当运用运算定律简算.
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