题目内容
计算下面各题,能用简便方法算的要用简便方法算
×
+
÷
×[(
-
)÷
]
-
+
×
25×1.25×4×8.
7 |
13 |
5 |
6 |
5 |
6 |
13 |
6 |
4 |
15 |
3 |
4 |
2 |
5 |
15 |
4 |
7 |
8 |
4 |
5 |
3 |
8 |
1 |
3 |
25×1.25×4×8.
(1)
×
+
÷
,
=
×
+
×
,
=(
+
)×
,
=1×
,
=
;
(2)
×[(
-
)÷
],
=
×[(
-
)×
],
=
×[
×
],
=
×
,
=
;
(3)
-
+
×
=
-
+
,
=
+
-
,
=1-
,
=
;
(4)25×1.25×4×8,
=(25×4)×(1.25×8),
=100×10,
=1000.
7 |
13 |
5 |
6 |
5 |
6 |
13 |
6 |
=
7 |
13 |
5 |
6 |
5 |
6 |
6 |
13 |
=(
7 |
13 |
6 |
13 |
5 |
6 |
=1×
5 |
6 |
=
5 |
6 |
(2)
4 |
15 |
3 |
4 |
2 |
5 |
15 |
4 |
=
4 |
15 |
15 |
20 |
8 |
20 |
4 |
15 |
=
4 |
15 |
7 |
20 |
4 |
15 |
=
4 |
15 |
7 |
75 |
=
28 |
1125 |
(3)
7 |
8 |
4 |
5 |
3 |
8 |
1 |
3 |
=
7 |
8 |
4 |
5 |
1 |
8 |
=
7 |
8 |
1 |
8 |
4 |
5 |
=1-
4 |
5 |
=
1 |
5 |
(4)25×1.25×4×8,
=(25×4)×(1.25×8),
=100×10,
=1000.
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