题目内容
下列各题怎样算简便就怎样算
(1)
| (2)(13+
| (3)
| (4)
|
(1)
÷
+
×7
=
×7+
×7
=(
+
)×7
=1×7
=7;
(2)(13+
)÷13
=(13+
)×
=13×
+
×
=1+
=1
;
(3)
×
÷
×3
=
×
×
×3
=(
×
)×(
×3)
=3×
=8;
(4)
x+
x=9.5
+
x=9.5
x=9.5
x=9.5÷
x=19.
1 |
55 |
1 |
7 |
54 |
55 |
=
1 |
55 |
54 |
55 |
=(
1 |
55 |
54 |
55 |
=1×7
=7;
(2)(13+
13 |
15 |
=(13+
13 |
15 |
1 |
13 |
=13×
1 |
13 |
13 |
15 |
1 |
13 |
=1+
1 |
15 |
=1
1 |
15 |
(3)
5 |
7 |
8 |
9 |
5 |
21 |
=
5 |
7 |
8 |
9 |
21 |
5 |
=(
5 |
7 |
21 |
5 |
8 |
9 |
=3×
8 |
3 |
=8;
(4)
1 |
3 |
1 |
6 |
1 |
3 |
1 |
6 |
1 |
2 |
x=9.5÷
1 |
2 |
x=19.
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