问题 解答题
下面各题怎样简便就怎样算.
5÷(7÷11)÷(11÷16)÷(16÷35)
28.67×67+3
1
5
×286.7+573.4×
1
20

10×(4
2
5
+2
1
2
)-1÷12.5%
1991+19911991+199119911991+…
2002+20022002+200220022002+…
答案

(1)5÷(7÷11)÷(11÷16)÷(16÷35),

=5÷

7
11
÷
11
16
÷
16
35

=5×

11
7
×
16
11
×
35
16

=25;

(2)28.67×67+3

1
5
×286.7+573.4×
1
20

=28.67×67+3.2×286.7+573.4×0.05,

=28.67×67+32×28.67+28.67,

=(67+32+1)×28.67,

=100×28.67,

=2867;

(3)10×(4

2
5
+2
1
2
)-1÷12.5%,

=10×(4.4+2.5)-1÷

1
8

=10×6.9-1×

1
8

=69-8,

=61;

(4)

1991+19911991+199119911991+…
2002+20022002+200220022002+…

=

1991×(1+10001+100010001+…)
2002×(1+10001+100010001+…)

=

1991
2002

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