题目内容
用合理的方法计算:
(1)4
+7
+
;
(2)8
-3
-2
;
(3)9
-(8
-7
);
(4)11
-8
+5
;
(5)52
×
+51
×
+50
×
;
(6)(2
+3
+4
)÷(2
+3
+4
).
(1)4
| 3 |
| 5 |
| 5 |
| 12 |
| 2 |
| 5 |
(2)8
| 11 |
| 17 |
| 8 |
| 15 |
| 7 |
| 15 |
(3)9
| 5 |
| 12 |
| 5 |
| 12 |
| 6 |
| 19 |
(4)11
| 9 |
| 17 |
| 12 |
| 25 |
| 12 |
| 25 |
(5)52
| 1 |
| 2 |
| 2 |
| 3 |
| 1 |
| 4 |
| 4 |
| 5 |
| 1 |
| 6 |
| 6 |
| 7 |
(6)(2
| 5 |
| 12 |
| 5 |
| 8 |
| 5 |
| 6 |
| 1 |
| 12 |
| 1 |
| 8 |
| 1 |
| 6 |
(1)4
+7
+
,
=4
+
+7
,
=5+7
,
=12
;
(2)8
-3
-2
,
=8
-(3
+2
),
=8
-6,
=2
;
(3)9
-(8
-7
),
=9
-8
+7
,
=1+7
,
=8
;
(4)11
-8
+5
,
=11
-(8
-5
),
=11
-3,
=8
;
(5)52
×
+51
×
+50
×
,
=(51+
)×
+(50+
)×
+(49+
)×
,
=51×
+
×
+50×
+
×
+49×
+
×
,
=34+1+40+1+42+1,
=(34+40+42)+(1+1+1),
=116+3,
=119;
(6)(2
+3
+4
)÷(2
+3
+4
),
=(2
+
+3
+
+4
+
)÷(2
+3
+4
),
=[(2+3+4)+(
+
+
)+(
+
+
)]÷[(2+3+4)+(
+
+
)],
=[9+
+
]÷(9+
),
=
÷
,
=
.
| 3 |
| 5 |
| 5 |
| 12 |
| 2 |
| 5 |
=4
| 3 |
| 5 |
| 2 |
| 5 |
| 5 |
| 12 |
=5+7
| 5 |
| 12 |
=12
| 5 |
| 12 |
(2)8
| 11 |
| 17 |
| 8 |
| 15 |
| 7 |
| 15 |
=8
| 11 |
| 17 |
| 8 |
| 15 |
| 7 |
| 15 |
=8
| 11 |
| 17 |
=2
| 11 |
| 17 |
(3)9
| 5 |
| 12 |
| 5 |
| 12 |
| 6 |
| 19 |
=9
| 5 |
| 12 |
| 5 |
| 12 |
| 6 |
| 19 |
=1+7
| 6 |
| 19 |
=8
| 6 |
| 19 |
(4)11
| 9 |
| 17 |
| 12 |
| 25 |
| 12 |
| 25 |
=11
| 9 |
| 17 |
| 12 |
| 25 |
| 12 |
| 25 |
=11
| 9 |
| 17 |
=8
| 9 |
| 17 |
(5)52
| 1 |
| 2 |
| 2 |
| 3 |
| 1 |
| 4 |
| 4 |
| 5 |
| 1 |
| 6 |
| 6 |
| 7 |
=(51+
| 3 |
| 2 |
| 2 |
| 3 |
| 5 |
| 4 |
| 4 |
| 5 |
| 7 |
| 6 |
| 6 |
| 7 |
=51×
| 2 |
| 3 |
| 3 |
| 2 |
| 2 |
| 3 |
| 4 |
| 5 |
| 5 |
| 4 |
| 4 |
| 5 |
| 6 |
| 7 |
| 7 |
| 6 |
| 6 |
| 7 |
=34+1+40+1+42+1,
=(34+40+42)+(1+1+1),
=116+3,
=119;
(6)(2
| 5 |
| 12 |
| 5 |
| 8 |
| 5 |
| 6 |
| 1 |
| 12 |
| 1 |
| 8 |
| 1 |
| 6 |
=(2
| 1 |
| 12 |
| 4 |
| 12 |
| 1 |
| 8 |
| 4 |
| 8 |
| 1 |
| 6 |
| 4 |
| 6 |
| 1 |
| 12 |
| 1 |
| 8 |
| 1 |
| 6 |
=[(2+3+4)+(
| 1 |
| 12 |
| 1 |
| 8 |
| 1 |
| 6 |
| 1 |
| 3 |
| 1 |
| 2 |
| 2 |
| 3 |
| 1 |
| 12 |
| 1 |
| 8 |
| 1 |
| 6 |
=[9+
| 3 |
| 8 |
| 3 |
| 2 |
| 3 |
| 8 |
=
| 87 |
| 8 |
| 75 |
| 8 |
=
| 29 |
| 25 |
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