题目内容
脱式计算,能简算的要简算.
(7.6-1
|
75%×0.375+1.625×
|
24-4.62-5.38 | ||||||||||||
1.25×2.5×32 | [
|
|
分析:(1)先分别计算两个小括号里面的加减法,再算括号外的除法;
(2)运用乘法分配律简算;
(3)根据减法的性质简算;
(4)先把32分解成4×8,再运用乘法结合律简算;
(5)先算小括号里面的加法,再算中括号里面的减法,最后算括号外的除法;
(6)先算小括号里面的减法,再算中括号里面的乘法,最后算括号外的除法.
(2)运用乘法分配律简算;
(3)根据减法的性质简算;
(4)先把32分解成4×8,再运用乘法结合律简算;
(5)先算小括号里面的加法,再算中括号里面的减法,最后算括号外的除法;
(6)先算小括号里面的减法,再算中括号里面的乘法,最后算括号外的除法.
解答:解:(1)(7.6-1
+80%)÷(1-30%),
=(6.2+0.8)÷(1-0.3),
=7÷0.7,
=10;
(2)75%×0.375+1.625×
-0.75,
=0.75×(0.375+1.625-1),
=0.75×1,
=0.75;
(3)24-4.62-5.38,
=24-(4.62+5.38),
=24-10,
=14;
(4)1.25×2.5×32,
=1.25×2.5×4×8,
=(1.25×8)×(2.5×4),
=10×10,
=100;
(5)[
-(25%+
)]÷10%,
=[
-0.6]÷10%,
=0.15÷0.1,
=1.5;
(6)
÷[(
-
)×
],
=
÷[
×
],
=
÷
,
=5.
2 |
5 |
=(6.2+0.8)÷(1-0.3),
=7÷0.7,
=10;
(2)75%×0.375+1.625×
3 |
4 |
=0.75×(0.375+1.625-1),
=0.75×1,
=0.75;
(3)24-4.62-5.38,
=24-(4.62+5.38),
=24-10,
=14;
(4)1.25×2.5×32,
=1.25×2.5×4×8,
=(1.25×8)×(2.5×4),
=10×10,
=100;
(5)[
3 |
4 |
7 |
20 |
=[
3 |
4 |
=0.15÷0.1,
=1.5;
(6)
1 |
3 |
11 |
12 |
5 |
6 |
4 |
5 |
=
1 |
3 |
1 |
12 |
4 |
5 |
=
1 |
3 |
1 |
15 |
=5.
点评:此题主要考查分数、整数、小数的四则混合运算的运算顺序和应用运算定律进行简便计算.
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