题目内容
计算,能简算的要简算
①4.8×1
|
②(
| ||||||||||||||||||
③(
|
④4-
| ||||||||||||||||||
⑤
|
⑥
|
分析:①根据乘法分配律进行计算;
②先算加法,再算除法;
③先算小括号里面的减法和乘法,再算除法;
④先算除法,再根据连减的性质进行计算;
⑤根据乘法分配律进行计算;
⑥前一个分数的分母与后一个分数的分子进行约分,然后再进一步计算即可.
②先算加法,再算除法;
③先算小括号里面的减法和乘法,再算除法;
④先算除法,再根据连减的性质进行计算;
⑤根据乘法分配律进行计算;
⑥前一个分数的分母与后一个分数的分子进行约分,然后再进一步计算即可.
解答:解:
①4.8×1
+4
÷
,
=4.8×
+4.2×
,
=(4.8+4.2)×
,
=9×
,
=15;
②(
+
)÷
,
=
÷
,
=
;
③(
-
)÷(
×
),
=
÷
,
=1;
④4-
÷
-
,
=4-
-
,
=4-(
+
),
=4-
,
=2
;
⑤
×10-
×
-
×0.25,
=
×(10-
-0.25),
=
×9,
=5;
⑥
×
×
×
×…×
,
=
.
①4.8×1
2 |
3 |
1 |
5 |
3 |
5 |
=4.8×
5 |
3 |
5 |
3 |
=(4.8+4.2)×
5 |
3 |
=9×
5 |
3 |
=15;
②(
3 |
17 |
5 |
34 |
4 |
51 |
=
11 |
34 |
4 |
51 |
=
33 |
8 |
③(
1 |
2 |
2 |
5 |
4 |
5 |
1 |
8 |
=
1 |
10 |
1 |
10 |
=1;
④4-
7 |
24 |
48 |
48 |
7 |
9 |
=4-
7 |
24 |
7 |
9 |
=4-(
7 |
24 |
7 |
9 |
=4-
77 |
72 |
=2
67 |
72 |
⑤
5 |
9 |
5 |
9 |
3 |
4 |
5 |
9 |
=
5 |
9 |
3 |
4 |
=
5 |
9 |
=5;
⑥
1 |
2 |
2 |
3 |
3 |
4 |
4 |
5 |
2011 |
2012 |
=
1 |
2012 |
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律简便计算.

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