题目内容
简便计算
÷
+
×
(
+
)×30
×
+
×
87×
×4+
.
7 |
9 |
11 |
5 |
2 |
9 |
5 |
11 |
(
5 |
6 |
4 |
5 |
1 |
2 |
1 |
15 |
1 |
3 |
1 |
2 |
87×
3 |
86 |
2 |
5 |
2 |
5 |
考点:运算定律与简便运算
专题:运算定律及简算
分析:①
÷
+
×
,把除数转化为乘它的倒数,再运用乘法分配律简算;
②(
+
)×30,运用乘法分配律简算;
③
×
+
×
,运用乘法分配律简算;
④87×
,转化为:(86+1)×
,运用乘法分配律简算;
⑤
×4+
,运用乘法分配律简算.
7 |
9 |
11 |
5 |
2 |
9 |
5 |
11 |
②(
5 |
6 |
4 |
5 |
③
1 |
2 |
1 |
15 |
1 |
3 |
1 |
2 |
④87×
3 |
86 |
3 |
86 |
⑤
2 |
5 |
2 |
5 |
解答:
解:①
÷
+
×
=(
+
)×
=1×
=
;
②(
+
)×30
=
×30+
×30
=25+24
=49;
③
×
+
×
=
×(
+
)
=
×
=
;
④87×
=(86+1)×
=86×
+1×
=3+
=3
;
⑤
×4+
=
×(4+1)
=
×5
=2.
7 |
9 |
11 |
5 |
2 |
9 |
5 |
11 |
=(
7 |
9 |
2 |
9 |
5 |
11 |
=1×
5 |
11 |
=
5 |
11 |
②(
5 |
6 |
4 |
5 |
=
5 |
6 |
4 |
5 |
=25+24
=49;
③
1 |
2 |
1 |
15 |
1 |
3 |
1 |
2 |
=
1 |
2 |
1 |
15 |
1 |
3 |
=
1 |
2 |
6 |
15 |
=
1 |
5 |
④87×
3 |
86 |
=(86+1)×
3 |
86 |
=86×
3 |
86 |
3 |
86 |
=3+
3 |
86 |
=3
3 |
86 |
⑤
2 |
5 |
2 |
5 |
=
2 |
5 |
=
2 |
5 |
=2.
点评:此题考查的目的是理解掌握乘法分配律的意义,并且能够灵活运用乘法分配律进行简便计算.
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