做一道旧题

大酱风度

大酱风度
脚踏实地，耕耘生活
首页 文章页 文章列表 博文目录
给我悄悄话
打印 被阅读次数

https://bbs.wenxuecity.com/netiq/138479.html

从1001到4999, 去掉千位上的数字，剩下的数有多少是原四位数的因子？

1. 1000=2^3×5^3 

故1000有16个因子,其中15个小于1000.

2. 2000=2^4×5^3, 2000有20个因子，小于1000的有18个。

类似的3000有32个因子，小于1000的有29个。

4000有24个因子，小于1000的有21个。

总计  15+18+29+21=83个

 

登录后才可评论.
Logo

Looks like your ad blocker is on.

×

We rely on ads to keep creating quality content for you to enjoy for free.

Please support our site by disabling your ad blocker.

Continue without supporting us

Choose your Ad Blocker

  • Adblock Plus
  • Adblock
  • Adguard
  • Ad Remover
  • Brave
  • Ghostery
  • uBlock Origin
  • uBlock
  • UltraBlock
  • Other
  1. In the extension bar, click the AdBlock Plus icon
  2. Click the large blue toggle for this website
  3. Click refresh
  1. In the extension bar, click the AdBlock icon
  2. Under "Pause on this site" click "Always"
  1. In the extension bar, click on the Adguard icon
  2. Click on the large green toggle for this website
  1. In the extension bar, click on the Ad Remover icon
  2. Click "Disable on This Website"
  1. In the extension bar, click on the orange lion icon
  2. Click the toggle on the top right, shifting from "Up" to "Down"
  1. In the extension bar, click on the Ghostery icon
  2. Click the "Anti-Tracking" shield so it says "Off"
  3. Click the "Ad-Blocking" stop sign so it says "Off"
  4. Refresh the page
  1. In the extension bar, click on the uBlock Origin icon
  2. Click on the big, blue power button
  3. Refresh the page
  1. In the extension bar, click on the uBlock icon
  2. Click on the big, blue power button
  3. Refresh the page
  1. In the extension bar, click on the UltraBlock icon
  2. Check the "Disable UltraBlock" checkbox
  1. Please disable your Ad Blocker
  2. Disable any DNS blocking tools such as AdGuardDNS or NextDNS

If the prompt is still appearing, please disable any tools or services you are using that block internet ads (e.g. DNS Servers).

Logo