题目内容
简便运算
(1)
|
(2)99×
| ||||||||||||
| (3)9.99×22.2+33.3×3.34 | (4)
|
(1)
×18-7×
-
,
=
×(18-7-1),
=
×10,
=6;
(2)99×
,
=(98+1)×
,
=98×
+1×
,
=97+
,
=97
;
(3)9.99×22.2+33.3×3.34,
=19.98×11.1+11.1×10.02,
=(19.98+10.02)×11.1,
=30×11.1,
=333;
(4)
+
+
+
+
+
,
=[(1-
)+(
-
)+(
-
)+(
-
)+(
-
)+(
-
)]×
,
=[1-
]×
,
=
×
,
=
.
| 3 |
| 5 |
| 3 |
| 5 |
| 3 |
| 5 |
=
| 3 |
| 5 |
=
| 3 |
| 5 |
=6;
(2)99×
| 97 |
| 98 |
=(98+1)×
| 97 |
| 98 |
=98×
| 97 |
| 98 |
| 97 |
| 98 |
=97+
| 97 |
| 98 |
=97
| 97 |
| 98 |
(3)9.99×22.2+33.3×3.34,
=19.98×11.1+11.1×10.02,
=(19.98+10.02)×11.1,
=30×11.1,
=333;
(4)
| 1 |
| 3 |
| 1 |
| 15 |
| 1 |
| 35 |
| 1 |
| 63 |
| 1 |
| 99 |
| 1 |
| 143 |
=[(1-
| 1 |
| 3 |
| 1 |
| 3 |
| 1 |
| 5 |
| 1 |
| 5 |
| 1 |
| 7 |
| 1 |
| 7 |
| 1 |
| 9 |
| 1 |
| 9 |
| 1 |
| 11 |
| 1 |
| 11 |
| 1 |
| 13 |
| 1 |
| 2 |
=[1-
| 1 |
| 13 |
| 1 |
| 2 |
=
| 12 |
| 13 |
| 1 |
| 2 |
=
| 6 |
| 13 |
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