题目内容
脱式计算,能简算的要简算.
762-408÷4×5 | 35×
|
1.5×[0.02÷(2.1-2.09)] | ||||||
12.5×8.8 | 87.58-(7.58+3.8) | (
|
分析:(1)先算除法,再算乘法,最后算减法,
(2)先同时求出两个乘法算式的积,再算加法,
(3)先算小括号里的减法,再算中括号里的除法,最后算括号外的乘法,
(4)把8.8化成8+0.8,运用乘法分配律进行简算,
(5)先去括号,再从左向右进行计算即可,
(6)先运用乘法的分配律进行简算,
(2)先同时求出两个乘法算式的积,再算加法,
(3)先算小括号里的减法,再算中括号里的除法,最后算括号外的乘法,
(4)把8.8化成8+0.8,运用乘法分配律进行简算,
(5)先去括号,再从左向右进行计算即可,
(6)先运用乘法的分配律进行简算,
解答:解:(1)762-408÷4×5,
=762-102×5,
=762-510,
=252;
(2)35×
+
×14,
=10+10,
=20;
(3)1.5×[0.02÷(2.1-2.09)],
=1.5×[0.02÷0.01],
=1.5×2,
=3;
(4)12.5×8.8,
=12.5×(8+0.8),
=12.5×8+12.5×0.8,
=100+10,
=110;
(5)87.58-(7.58+3.8),
=87.58-7.58-3.8,
=80-3.8,
=76.2;
(6)(
+
)×4+
,
=
×4+
×4+
,
=
+
+
,
=
+(
+
),
═
+1,
=1
.
=762-102×5,
=762-510,
=252;
(2)35×
2 |
7 |
5 |
7 |
=10+10,
=20;
(3)1.5×[0.02÷(2.1-2.09)],
=1.5×[0.02÷0.01],
=1.5×2,
=3;
(4)12.5×8.8,
=12.5×(8+0.8),
=12.5×8+12.5×0.8,
=100+10,
=110;
(5)87.58-(7.58+3.8),
=87.58-7.58-3.8,
=80-3.8,
=76.2;
(6)(
2 |
9 |
2 |
19 |
11 |
19 |
=
2 |
9 |
2 |
19 |
11 |
19 |
=
8 |
9 |
8 |
19 |
11 |
19 |
=
8 |
9 |
8 |
19 |
11 |
19 |
═
8 |
9 |
=1
8 |
9 |
点评:考查了整数、分数四则混合运算的顺序,注意灵活运用运算定律进行简算.
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