题目内容
脱式计算,能简算的要简算.
0.125×0.25×32
1500-18×120÷25
×101-0.75
÷[
×(0.4+
)]
÷[(
+
)×
].
0.125×0.25×32
1500-18×120÷25
3 |
4 |
9 |
20 |
3 |
2 |
4 |
5 |
4 |
5 |
1 |
3 |
2 |
5 |
4 |
11 |
分析:(1)把32看作4×8,运用乘法交换律与结合律简算;
(2)先算乘除,再算减法;
(3)把分数改为小数0.75,运用乘法分配律简算;
(4)(5)题先算小括号内的,再算中括号内的,最后算括号外的.
(2)先算乘除,再算减法;
(3)把分数改为小数0.75,运用乘法分配律简算;
(4)(5)题先算小括号内的,再算中括号内的,最后算括号外的.
解答:解:(1)0.125×0.25×32,
=0.125×0.25×4×8,
=0.125×8×(0.25×4),
=1×1,
=1;
(2)1500-18×120÷25,
=1500-86.4,
=1413.6;
(3)
×101-0.75,
=0.75×101-0.75,
=(101-1)×0.75,
=100×0.75,
=75;
(4)
÷[
×(0.4+
)],
=
÷[
×(
+
)],
=
÷[
×
],
=
÷
,
=
×
,
=
;
(5)
÷[(
+
)×
],
=
÷[
×
],
=
÷
,
=
×
,
=3.
=0.125×0.25×4×8,
=0.125×8×(0.25×4),
=1×1,
=1;
(2)1500-18×120÷25,
=1500-86.4,
=1413.6;
(3)
3 |
4 |
=0.75×101-0.75,
=(101-1)×0.75,
=100×0.75,
=75;
(4)
9 |
20 |
3 |
2 |
4 |
5 |
=
9 |
20 |
3 |
2 |
2 |
5 |
4 |
5 |
=
9 |
20 |
3 |
2 |
6 |
5 |
=
9 |
20 |
9 |
5 |
=
9 |
20 |
5 |
9 |
=
1 |
4 |
(5)
4 |
5 |
1 |
3 |
2 |
5 |
4 |
11 |
=
4 |
5 |
11 |
15 |
4 |
11 |
=
4 |
5 |
4 |
15 |
=
4 |
5 |
15 |
4 |
=3.
点评:此题考查了四则混合运算.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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