题目内容
计算:(能用简便方法的用简便方法计算)
| 25×
|
| ||||||||||||
3-
|
| 150-144×
|
考点:分数的四则混合运算,分数的简便计算
专题:运算顺序及法则,运算定律及简算
分析:(1)先计算小括号里的加法,再计算括号外边的乘法;
(2)根据乘法的分配律解答即可;
(3)把99看作98+1,然后再根据乘法的分配律解答即可;
(4)先算乘法,再算减法;
(5)按从左到右的顺序计算;
(6)先算乘法,再算减法.
(2)根据乘法的分配律解答即可;
(3)把99看作98+1,然后再根据乘法的分配律解答即可;
(4)先算乘法,再算减法;
(5)按从左到右的顺序计算;
(6)先算乘法,再算减法.
解答:
解:(1)
×(
+
)
=
×
=
(2)25×
+25×
=25×(
+
)
=25×1
=25
(3)
×99
=
×(98+1)
=
×98+
=37
(4)3-
×
=3-
=2
(5)
×
×
=
×
=
(6)150-144×
=150-120
=30
2 |
5 |
1 |
2 |
5 |
6 |
=
2 |
5 |
4 |
3 |
=
8 |
15 |
(2)25×
2 |
9 |
7 |
9 |
=25×(
2 |
9 |
7 |
9 |
=25×1
=25
(3)
37 |
98 |
=
37 |
98 |
=
37 |
98 |
37 |
98 |
=37
37 |
98 |
(4)3-
8 |
15 |
9 |
16 |
=3-
3 |
10 |
=2
7 |
10 |
(5)
3 |
7 |
2 |
3 |
7 |
8 |
=
2 |
7 |
7 |
8 |
=
1 |
4 |
(6)150-144×
5 |
6 |
=150-120
=30
点评:本题考查了运算定律与简便运算以及四则混合运算.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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