题目内容
用简便方法计算.
×
×
12×(
+
)
×
+
×
31×
(
-
)×48
×11-
.
| 44 |
| 3 |
| 3 |
| 5 |
| 5 |
| 11 |
12×(
| 1 |
| 3 |
| 1 |
| 4 |
| 5 |
| 7 |
| 6 |
| 13 |
| 7 |
| 13 |
| 5 |
| 7 |
31×
| 19 |
| 30 |
(
| 1 |
| 6 |
| 1 |
| 8 |
| 7 |
| 10 |
| 7 |
| 10 |
(1)
×
×
,
=
×
,
=4;
(2)12×(
+
),
=12×
+12×
,
=4+3,
=7;
(3)
×
+
×
,
=
×(
+
),
=
×1,
=
;
(4)31×
,
=(30+1)×
,
=30×
+1×
,
=19+
,
=19
;
(5)(
-
)×48,
=
×48-
×48,
=8-6,
=2;
(6)
×11-
,
=
×(11-1),
=
×10,
=7.
| 44 |
| 3 |
| 3 |
| 5 |
| 5 |
| 11 |
=
| 44 |
| 5 |
| 5 |
| 11 |
=4;
(2)12×(
| 1 |
| 3 |
| 1 |
| 4 |
=12×
| 1 |
| 3 |
| 1 |
| 4 |
=4+3,
=7;
(3)
| 5 |
| 7 |
| 6 |
| 13 |
| 7 |
| 13 |
| 5 |
| 7 |
=
| 5 |
| 7 |
| 6 |
| 13 |
| 7 |
| 13 |
=
| 5 |
| 7 |
=
| 5 |
| 7 |
(4)31×
| 19 |
| 30 |
=(30+1)×
| 19 |
| 30 |
=30×
| 19 |
| 30 |
| 19 |
| 30 |
=19+
| 19 |
| 30 |
=19
| 19 |
| 30 |
(5)(
| 1 |
| 6 |
| 1 |
| 8 |
=
| 1 |
| 6 |
| 1 |
| 8 |
=8-6,
=2;
(6)
| 7 |
| 10 |
| 7 |
| 10 |
=
| 7 |
| 10 |
=
| 7 |
| 10 |
=7.
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