Re: [計量] 問一題數學
※ 引述《doublechiu (...)》之銘言：
: Each of the following numbers has one digit blotted out. Which of the numbers
: could be the sum of two consecutive odd integers?
: Indicate all such sums
: a.2,□24
: b.3,□32
: c.5,□54
: d.6,□48
: e.9,□62
: 答案是abd
: 我本來想說奇數相加尾數只可能是4或8
: 不過答案好像不是這樣> <
設N是任意正整數
設一個奇數為2N+1,另一個為2N+3
兩數之合為(2N+1)+(2N+3)=4N+4 => 4(N+1)
所以兩數之合為4的倍數
就找末兩位是4的倍數就是答案了
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推
07/22 01:01, , 1F
07/22 01:01, 1F
→
07/22 01:03, , 2F
07/22 01:03, 2F
→
07/22 01:04, , 3F
07/22 01:04, 3F
→
07/22 01:04, , 4F
07/22 01:04, 4F
推
07/22 18:35, , 5F
07/22 18:35, 5F
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