题目内容
计算各题,能简算的要简算. 4
|
| [
| ||||||||||||||||||||||
798+10570÷35 |
| 12.5×3.2×2.5 |
考点:分数的四则混合运算
专题:运算顺序及法则
分析:(1)根据减法的性质进行简算;
(2)根据乘法分配律进行简算;
(3)先算小括号里面的减法,再算中括号里面的减法,最后算除法;
(4)先算除法,再算加法;
(5)先算乘法,再算加法,最后算除法;
(6)根据乘法交换律和结合律进行简算.
(2)根据乘法分配律进行简算;
(3)先算小括号里面的减法,再算中括号里面的减法,最后算除法;
(4)先算除法,再算加法;
(5)先算乘法,再算加法,最后算除法;
(6)根据乘法交换律和结合律进行简算.
解答:
解:(1)4
-(1
+1
)
=4
-1
-1
=4
-1
-1
=3-1
=1
;
(2)
×
+
÷
=
×
+
×
=
×(
+
)
=
×1
=
;
(3)[
-(
-
)]÷
=[
-
]÷
=
÷
=
;
(4)798+10570÷35
=798+302
=1100;
(5)
÷(
+
×
)
=
÷(
+
)
=
÷
=
;
(6)12.5×3.2×2.5
=12.5×(4×0.8)×2.5
=(12.5×0.8)×(4×2.5)
=10×10
=100.
5 |
7 |
5 |
17 |
5 |
7 |
=4
5 |
7 |
5 |
17 |
5 |
7 |
=4
5 |
7 |
5 |
7 |
5 |
17 |
=3-1
5 |
17 |
=1
12 |
17 |
(2)
4 |
3 |
2 |
7 |
5 |
7 |
3 |
4 |
=
4 |
3 |
2 |
7 |
5 |
7 |
4 |
3 |
=
4 |
3 |
2 |
7 |
5 |
7 |
=
4 |
3 |
=
4 |
3 |
(3)[
1 |
2 |
3 |
4 |
3 |
5 |
7 |
10 |
=[
1 |
2 |
3 |
20 |
7 |
10 |
=
7 |
20 |
7 |
10 |
=
1 |
2 |
(4)798+10570÷35
=798+302
=1100;
(5)
1 |
4 |
5 |
8 |
3 |
8 |
8 |
5 |
=
1 |
4 |
5 |
8 |
3 |
5 |
=
1 |
4 |
49 |
40 |
=
10 |
49 |
(6)12.5×3.2×2.5
=12.5×(4×0.8)×2.5
=(12.5×0.8)×(4×2.5)
=10×10
=100.
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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