题目内容
能简算的要简算.
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9×(
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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
×
×28×22,运用乘法交换律和结合律简算;
②
×
×
,先约分,再计算;
③
+(
-
),先算括号里面的减法,再算加法;
④
+
+
+
,运用加法交换律和结合律简算;
⑤
+
-
+
,根据加、减法的运算性质以及加法的运算定律进行简算;
⑥
-
+
-
,根据减法的运算性质以及加法的运算定律进行简算;
⑦9×(
+
)运用乘法分配律简算;
⑧
×
+
×
运用乘法分配律简算.
| 7 |
| 11 |
| 5 |
| 14 |
②
| 37 |
| 10 |
| 5 |
| 6 |
| 3 |
| 8 |
③
| 1 |
| 2 |
| 2 |
| 3 |
| 1 |
| 4 |
④
| 5 |
| 14 |
| 7 |
| 18 |
| 9 |
| 14 |
| 5 |
| 18 |
⑤
| 5 |
| 8 |
| 7 |
| 15 |
| 5 |
| 8 |
| 2 |
| 15 |
⑥
| 5 |
| 13 |
| 2 |
| 11 |
| 8 |
| 13 |
| 9 |
| 11 |
⑦9×(
| 1 |
| 3 |
| 2 |
| 9 |
⑧
| 3 |
| 8 |
| 11 |
| 13 |
| 3 |
| 8 |
| 2 |
| 13 |
解答:
解:①
×
×28×22
=(
×22)×(
×28)
=14×10
=140;
②
×
×
=
×
=
;
③
+(
-
)
=
+
=
;
④
+
+
+
=(
+
)+(
+
)
=1+
=1
;
⑤
+
-
+
=
-
+(
+
)
=0+
=
;
⑥
-
+
-
=
+
-(
+
)
=1-1
=0;
⑦9×(
+
)
=9×
+9×
=3+2
=5;
⑧
×
+
×
=(
+
)×
=1×
=
.
| 7 |
| 11 |
| 5 |
| 14 |
=(
| 7 |
| 11 |
| 5 |
| 14 |
=14×10
=140;
②
| 37 |
| 10 |
| 5 |
| 6 |
| 3 |
| 8 |
=
| 37 |
| 12 |
| 3 |
| 8 |
=
| 37 |
| 32 |
③
| 1 |
| 2 |
| 2 |
| 3 |
| 1 |
| 4 |
=
| 1 |
| 2 |
| 5 |
| 12 |
=
| 11 |
| 12 |
④
| 5 |
| 14 |
| 7 |
| 18 |
| 9 |
| 14 |
| 5 |
| 18 |
=(
| 5 |
| 14 |
| 9 |
| 14 |
| 7 |
| 18 |
| 5 |
| 18 |
=1+
| 2 |
| 3 |
=1
| 2 |
| 3 |
⑤
| 5 |
| 8 |
| 7 |
| 15 |
| 5 |
| 8 |
| 2 |
| 15 |
=
| 5 |
| 8 |
| 5 |
| 8 |
| 7 |
| 15 |
| 2 |
| 15 |
=0+
| 9 |
| 15 |
=
| 9 |
| 15 |
⑥
| 5 |
| 13 |
| 2 |
| 11 |
| 8 |
| 13 |
| 9 |
| 11 |
=
| 5 |
| 13 |
| 8 |
| 13 |
| 2 |
| 11 |
| 9 |
| 11 |
=1-1
=0;
⑦9×(
| 1 |
| 3 |
| 2 |
| 9 |
=9×
| 1 |
| 3 |
| 2 |
| 9 |
=3+2
=5;
⑧
| 3 |
| 8 |
| 11 |
| 13 |
| 3 |
| 8 |
| 2 |
| 13 |
=(
| 11 |
| 13 |
| 2 |
| 13 |
| 3 |
| 8 |
=1×
| 3 |
| 8 |
=
| 3 |
| 8 |
点评:此题考查的目的是理解掌握分数四则混合运算的顺序以及它们的计算法则,并且能够灵活选择简便方法进行计算.
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