题目内容
用递等式计算.
|
20-12÷
|
8-
| ||||||||||||||
| 48048÷12+88 | 9÷(
|
(1-0.8×
|
分析:(1)按照从左向右的顺序进行计算;
(2)先算除法,再算减法;
(3)先算除法,再根据减法的性质进行简算;
(4)先算除法,再算加法;
(5)先算减法,再算除法,最后算乘法;
(6)先算乘法,再算减法,最后算除法.
(2)先算除法,再算减法;
(3)先算除法,再根据减法的性质进行简算;
(4)先算除法,再算加法;
(5)先算减法,再算除法,最后算乘法;
(6)先算乘法,再算减法,最后算除法.
解答:解:
(1)
÷
×
,
=
×
,
=2;
(2)20-12÷
,
=20-15,
=5;
(3)8-
÷
-
,
=8-
-
,
=8-(
+
),
=8-4,
=4;
(4)48048÷12+88,
=4004+88,
=4092;
(5)9÷(
-
)×3,
=9÷
×3,
=81×3,
=243;
(6)(1-0.8×
)÷
,
=(1-0.6)÷
,
=0.4÷
,
=0.5.
(1)
| 5 |
| 6 |
| 1 |
| 4 |
| 3 |
| 5 |
=
| 10 |
| 3 |
| 3 |
| 5 |
=2;
(2)20-12÷
| 4 |
| 5 |
=20-15,
=5;
(3)8-
| 2 |
| 3 |
| 1 |
| 4 |
| 4 |
| 3 |
=8-
| 8 |
| 3 |
| 4 |
| 3 |
=8-(
| 8 |
| 3 |
| 4 |
| 3 |
=8-4,
=4;
(4)48048÷12+88,
=4004+88,
=4092;
(5)9÷(
| 7 |
| 9 |
| 2 |
| 3 |
=9÷
| 1 |
| 9 |
=81×3,
=243;
(6)(1-0.8×
| 3 |
| 4 |
| 4 |
| 5 |
=(1-0.6)÷
| 4 |
| 5 |
=0.4÷
| 4 |
| 5 |
=0.5.
点评:此题主要考查分数、整数、小数的四则混合运算的运算顺序和应用运算定律进行简便计算.
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