题目内容
| 用合理的方法计算 19
|
2.8×1
| ||||||||||
|
| ||||||||||
(
|
|
(1)19
×7,
=(19+
)×7,
=19×7+
×7,
=133+
,
=139
;
(2)2.8×1
+7
×1
,
=(2.8+7
)×1
,
=(2.8+7.2)×1
,
=10×
,
=
;
(3)
×0.91×
,
=(
×
)×0.91,
=
×0.91,
=0.14;
(4)
+
×
,
=
+
,
=
;
(5)(
+
)×
,
=
×
+
×
,
=
+
,
=
;
(6)
×99,
=
×(100-1),
=
×100-
×1,
=97-
,
=96
.
| 7 |
| 8 |
=(19+
| 7 |
| 8 |
=19×7+
| 7 |
| 8 |
=133+
| 49 |
| 8 |
=139
| 1 |
| 8 |
(2)2.8×1
| 3 |
| 4 |
| 1 |
| 5 |
| 3 |
| 4 |
=(2.8+7
| 1 |
| 5 |
| 3 |
| 4 |
=(2.8+7.2)×1
| 3 |
| 4 |
=10×
| 7 |
| 4 |
=
| 35 |
| 2 |
(3)
| 7 |
| 13 |
| 2 |
| 7 |
=(
| 7 |
| 13 |
| 2 |
| 7 |
=
| 2 |
| 13 |
=0.14;
(4)
| 5 |
| 8 |
| 3 |
| 8 |
| 2 |
| 15 |
=
| 5 |
| 8 |
| 1 |
| 20 |
=
| 27 |
| 40 |
(5)(
| 7 |
| 18 |
| 5 |
| 27 |
| 9 |
| 35 |
=
| 7 |
| 18 |
| 9 |
| 35 |
| 5 |
| 27 |
| 9 |
| 35 |
=
| 1 |
| 10 |
| 1 |
| 21 |
=
| 31 |
| 210 |
(6)
| 97 |
| 100 |
=
| 97 |
| 100 |
=
| 97 |
| 100 |
| 97 |
| 100 |
=97-
| 97 |
| 100 |
=96
| 3 |
| 100 |
练习册系列答案
相关题目