题目内容
(2013?天河区)用递等式计算.
| ①960÷30-10 | ②
|
③(
| ||||||||
| ④52-2.5×0.9×4 | ⑤
|
分析:①先算除法,再算减法;
②先算乘法,再算除法;
③根据乘法分配律进行计算;
④根据乘法交换律进行计算;
⑤先算减法,再算中括号里面的除法,再算括号外面的除法.
②先算乘法,再算除法;
③根据乘法分配律进行计算;
④根据乘法交换律进行计算;
⑤先算减法,再算中括号里面的除法,再算括号外面的除法.
解答:解:
①960÷30-10,
=32-10,
=22;
②
×2÷
,
=
÷
,
=
;
③(
+
)×36,
=
×36+
×36,
=20+42,
=62;
④52-2.5×0.9×4,
=52-2.5×4×0.9,
=52-10×0.9,
=52-9,
=43;
⑤
÷[(
-
)÷
],
=
÷[
÷
],
=
÷
,
=
.
①960÷30-10,
=32-10,
=22;
②
| 5 |
| 6 |
| 30 |
| 31 |
=
| 5 |
| 3 |
| 30 |
| 31 |
=
| 31 |
| 18 |
③(
| 5 |
| 9 |
| 7 |
| 6 |
=
| 5 |
| 9 |
| 7 |
| 6 |
=20+42,
=62;
④52-2.5×0.9×4,
=52-2.5×4×0.9,
=52-10×0.9,
=52-9,
=43;
⑤
| 7 |
| 8 |
| 3 |
| 4 |
| 1 |
| 2 |
| 4 |
| 5 |
=
| 7 |
| 8 |
| 1 |
| 4 |
| 4 |
| 5 |
=
| 7 |
| 8 |
| 5 |
| 16 |
=
| 14 |
| 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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