题目内容
| 脱式计算.(能简算的要简算) 37×40+1035÷23 |
1.3-3.79+9.7-6.21 |
| ||||||||||||||||
7+
|
|
270÷[36÷(1-
|
考点:整数四则混合运算,运算定律与简便运算,分数的四则混合运算,小数四则混合运算
专题:运算顺序及法则,运算定律及简算
分析:(1)先算乘法和除法,再算加法;
(2)利用加法交换律与结合律简算;
(3)先算加法,再算除法;
(4)先算乘法,再利用加法结合律简算;
(5)利用乘法分配律简算;
(6)先算减法,再算括号里面的除法,最后算括号外面的除法.
(2)利用加法交换律与结合律简算;
(3)先算加法,再算除法;
(4)先算乘法,再利用加法结合律简算;
(5)利用乘法分配律简算;
(6)先算减法,再算括号里面的除法,最后算括号外面的除法.
解答:
解:(1)37×40+1035÷23
=1480+45
=1525;
(2)1.3-3.79+9.7-6.21
=1.3+9.7-(6.21+3.79)
=11-10
=1;
(3)
÷(
+
)
=
×
=
;
(4)7+
×
+
=7+
+
=7+(
+
)
=7+1
=8;
(5)
×
+
÷
=
×
+
×
=
×(
+
)
=
×1
=
;
(6)270÷[36÷(1-
)]
=270÷[36×
]
=270÷45
=6.
=1480+45
=1525;
(2)1.3-3.79+9.7-6.21
=1.3+9.7-(6.21+3.79)
=11-10
=1;
(3)
| 1 |
| 24 |
| 1 |
| 8 |
| 1 |
| 3 |
=
| 1 |
| 24 |
| 24 |
| 11 |
=
| 1 |
| 11 |
(4)7+
| 1 |
| 6 |
| 3 |
| 4 |
| 7 |
| 8 |
=7+
| 1 |
| 8 |
| 7 |
| 8 |
=7+(
| 1 |
| 8 |
| 7 |
| 8 |
=7+1
=8;
(5)
| 9 |
| 20 |
| 11 |
| 25 |
| 14 |
| 25 |
| 20 |
| 9 |
=
| 9 |
| 20 |
| 11 |
| 25 |
| 14 |
| 25 |
| 9 |
| 20 |
=
| 9 |
| 20 |
| 11 |
| 25 |
| 14 |
| 25 |
=
| 9 |
| 20 |
=
| 9 |
| 20 |
(6)270÷[36÷(1-
| 1 |
| 5 |
=270÷[36×
| 5 |
| 4 |
=270÷45
=6.
点评:混合运算的关键是抓住运算顺序,正确按运算顺序计算,灵活运用运算定律简算.
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