题目内容
灵活计算.
|
| 72×(
| ||||||||||||||||||
(
| (
|
|
(1)
×
+
÷13,
=
×
+
×
,
=
×(
+
),
=
×1,
=
;
(2)
÷(3-
-
),
=
÷[3-(
+
)],
=
÷[3-1],
=
÷2,
=
;
(3)72×(
-
-
),
=72×
-72×
-72×
,
=24-18-2,
=4;
(4)(
+
)×12+
,
=
×12+
×12+
,
=5+(
+
),
=6;
(5)(
-
×
)÷
,
=[
×(1-
)]×5,
=[
×
]×5,
=
×5,
=
;
(6)
×
×(2009×42×85),
=(
×42)×(
×85)×2009,
=2×5×2009,
=20090;
| 7 |
| 8 |
| 12 |
| 13 |
| 7 |
| 8 |
=
| 7 |
| 8 |
| 12 |
| 13 |
| 7 |
| 8 |
| 1 |
| 13 |
=
| 7 |
| 8 |
| 12 |
| 13 |
| 1 |
| 13 |
=
| 7 |
| 8 |
=
| 7 |
| 8 |
(2)
| 1 |
| 4 |
| 7 |
| 15 |
| 8 |
| 15 |
=
| 1 |
| 4 |
| 7 |
| 15 |
| 8 |
| 15 |
=
| 1 |
| 4 |
=
| 1 |
| 4 |
=
| 1 |
| 8 |
(3)72×(
| 1 |
| 3 |
| 1 |
| 4 |
| 1 |
| 36 |
=72×
| 1 |
| 3 |
| 1 |
| 4 |
| 1 |
| 36 |
=24-18-2,
=4;
(4)(
| 5 |
| 12 |
| 1 |
| 19 |
| 7 |
| 19 |
=
| 5 |
| 12 |
| 1 |
| 19 |
| 7 |
| 19 |
=5+(
| 12 |
| 19 |
| 7 |
| 19 |
=6;
(5)(
| 3 |
| 4 |
| 3 |
| 4 |
| 2 |
| 5 |
| 1 |
| 5 |
=[
| 3 |
| 4 |
| 2 |
| 5 |
=[
| 3 |
| 4 |
| 3 |
| 5 |
=
| 9 |
| 20 |
=
| 9 |
| 4 |
(6)
| 1 |
| 21 |
| 1 |
| 17 |
=(
| 1 |
| 21 |
| 1 |
| 17 |
=2×5×2009,
=20090;
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