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(1)3318+312÷24×205(2)47.1×9.4-47.1÷2-+47.1(3)[(1-0.5)×20]÷[(1+0.25)÷4](4)12−13+14(5)100-99+98-97+96-…+4-3+2-1(6)15×6+16×7+17×8+−−−−−−+149×50.

题目详情
(1)3318+312÷24×205                  
(2)47.1×9.4-47.1÷2-+47.1
(3)[(1-0.5)×20]÷[(1+0.25)÷4]
(4)
1
2
1
3
+
1
4

(5)100-99+98-97+96-…+4-3+2-1
(6)
1
5×6
+
1
6×7
+
1
7×8
+ −−−−−−+
1
49×50
▼优质解答
答案和解析
(1)3318+312÷24×205,
=3318+13×205,
=3318+2665,
=5983;
(2)47.1×9.4-47.1÷2-47.1,
=47.1×(9.4-0.5-1),
=47.1×7.9,
=372.09;
(3)[(1-0.5)×20]÷[(1+0.25)÷4],
=10÷0.3125,
=32;
(4)
1
2
1
3
+
1
4

=(
1
2
+
1
4
1
3

=
3
4
1
3

=
5
12

(5)100-99+98-97+96-…+4-3+2-1,
=(100-99)+(98-97)+(96-95)+…+(4-3)+(2-1),
=1×50,
=50;
(6)
1
5×6
+
1
6×7
+
1
7×8
+… +
1
49×50

=(
1
5
1
6
)+(
1
6
1
7
) +(
1
7
1
8
)+…+(
1
49
1
50
),
=
1
5
1
50

=
9
50