题目内容
计算下列各题,能简算的要简算.
|
2-
|
| ||||||||||||||||
| 37.84+2.5-7.84+7.5 |
|
8.8×4.18-0.18×8.8-8.8. |
分析:(1)先算减法,再算加法;
(2)根据减法的性质进行简算;
(3)先算减法,再算加法;
(4)根据加法交换律和结合律进行简算;
(5)先算小括号里面的减法,再算括号外面的减法;
(6)根据乘法分配律进行简算.
(2)根据减法的性质进行简算;
(3)先算减法,再算加法;
(4)根据加法交换律和结合律进行简算;
(5)先算小括号里面的减法,再算括号外面的减法;
(6)根据乘法分配律进行简算.
解答:解:(1)
+(
-
)
=
+
=
;
(2)2-
-
=2-(
+
)
=2-1
=1;
(3)
-
+
=
+
=
;
(4)37.84+2.5-7.84+7.5
=(37.84-7.84)+(2.5+7.5)
=30+10
=40;
(5)
-(
-
)
=
-
=
;
(6)8.8×4.18-0.18×8.8-8.8
=8.8×(4.18-0.18-1)
=8.8×3
=26.4.
| 4 |
| 5 |
| 3 |
| 8 |
| 1 |
| 4 |
=
| 4 |
| 5 |
| 1 |
| 8 |
=
| 37 |
| 40 |
(2)2-
| 3 |
| 7 |
| 4 |
| 7 |
=2-(
| 3 |
| 7 |
| 4 |
| 7 |
=2-1
=1;
(3)
| 5 |
| 8 |
| 1 |
| 3 |
| 5 |
| 12 |
=
| 7 |
| 24 |
| 5 |
| 12 |
=
| 17 |
| 24 |
(4)37.84+2.5-7.84+7.5
=(37.84-7.84)+(2.5+7.5)
=30+10
=40;
(5)
| 5 |
| 12 |
| 5 |
| 9 |
| 1 |
| 2 |
=
| 5 |
| 12 |
| 1 |
| 18 |
=
| 13 |
| 36 |
(6)8.8×4.18-0.18×8.8-8.8
=8.8×(4.18-0.18-1)
=8.8×3
=26.4.
点评:考查了运算定律与简便运算,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简便计算.
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