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(2006•武昌区)计算下面各题.1+3+5+…+21+231+O.45÷0.9-0.254÷45−45÷4[1−(12−14)]÷23.

题目详情
(2006•武昌区)
计算下面各题.
1+3+5+…+21+23

1+O.45÷0.9-0.25
4
5
4
5
÷4
[1−(
1
2
1
4
)]÷
2
3
▼优质解答
答案和解析
(1)1+3+5+…+21+23,
=(1+23)+(3+21)+…(11+13),
=24×6,
=144;

(2)1+O.45÷0.9-0.25,
=1+0.5-0.25,
=1.5-0.25,
=1.25;

(3)4÷
4
5
-
4
5
÷4,
=5-
1
5

=4
4
5


(4)[1-(
1
2
1
4
)]÷
2
3

=[1-
1
4
]÷
2
3

=
3
4
÷
2
3

=1
1
8