题目内容
计算下面各题,能简算的要简算.
①6÷
|
②99×
|
③(
|
④
|
分析:①同时运算两个除法,再算减法;
②先把99分解成98+1,再运用乘法分配律简算;
③先算小括号里面的加法,再算括号外的除法,最后算减法;
④先算小括号里面的加法,再算括号外的除法,最后算括号外的减法.
②先把99分解成98+1,再运用乘法分配律简算;
③先算小括号里面的加法,再算括号外的除法,最后算减法;
④先算小括号里面的加法,再算括号外的除法,最后算括号外的减法.
解答:解:①6÷
-
÷6,
=20-
,
=19
;
②99×
,
=(98+1)×
,
=98×
+1×
,
=97+
,
=97
;
③(
+
)÷
-
,
=
÷
-
,
=
-
,
=
;
④
-(
+
)÷
,
=
-
÷
,
=
-
,
=
.
| 3 |
| 10 |
| 3 |
| 10 |
=20-
| 1 |
| 20 |
=19
| 19 |
| 20 |
②99×
| 97 |
| 98 |
=(98+1)×
| 97 |
| 98 |
=98×
| 97 |
| 98 |
| 97 |
| 98 |
=97+
| 97 |
| 98 |
=97
| 97 |
| 98 |
③(
| 1 |
| 2 |
| 1 |
| 3 |
| 3 |
| 5 |
| 17 |
| 18 |
=
| 5 |
| 6 |
| 3 |
| 5 |
| 17 |
| 18 |
=
| 25 |
| 18 |
| 17 |
| 18 |
=
| 4 |
| 9 |
④
| 9 |
| 10 |
| 1 |
| 4 |
| 7 |
| 20 |
| 3 |
| 4 |
=
| 9 |
| 10 |
| 3 |
| 5 |
| 3 |
| 4 |
=
| 9 |
| 10 |
| 4 |
| 5 |
=
| 1 |
| 10 |
点评:本题考查了四则混合运算,注意运算顺序和运算法则,灵活运用所学的运算定律进行简便计算.
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